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Background. Increasing concern is evident about contamination of foodstuffs and natural health products. Methods. Common off-the-shelf varieties of black, green, white, and oolong teas sold in tea bags were used for analysis in this study. Toxic element testing was performed on 30 different teas by analyzing (i) tea leaves, (ii) tea steeped for 3-4 minutes, and (iii) tea steeped for 15-17 minutes. Results were compared to existing preferred endpoints. Results. All brewed teas contained lead with 73% of teas brewed for 3 minutes and 83% brewed for 15 minutes having lead levels considered unsafe for consumption during pregnancy and lactation. Aluminum levels were above recommended guidelines in 20% of brewed teas. No mercury was found at detectable levels in any brewed tea samples. Teas contained several beneficial elements such as magnesium, calcium, potassium, and phosphorus. Of trace minerals, only manganese levels were found to be excessive in some black teas. Conclusions. Toxic contamination by heavy metals was found in most of the teas sampled. Some tea samples are considered unsafe. There are no existing guidelines for routine testing or reporting of toxicant levels in "naturally" occurring products. Public health warnings or industry regulation might be indicated to protect consumer safety.
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Hindawi Publishing Corporation
Journal of Toxicology
Volume , Article ID , pages
http://dx.doi.org/.//
Research Article
The Benefits and Risks of Consuming Brewed Tea:
Beware of Toxic Element Contamination
Gerry Schwalfenberg,1Stephen J. Genuis,2and Ilia Rodushkin3
1University of Alberta, Number 301, 9509-156 Street, Edmonton, AB, Canada T5P 4J5
2University of Alberta, 2935-66 Street, Edmonton, AB, Canada T6K 4C1
3Lule˚
a University of Technology, Aurorum 10, 977 75 Lule˚
a, Sweden
Correspondence should be addressed to Gerry Schwalfenberg; gschwalf@shaw.ca
Received  July ; Accepted  September 
Academic Editor: Lucio Guido Costa
Copyright ©  Gerry Schwalfenberg et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Background. Increasing concern is evident about contamination of foodstus and natural health products. Methods.Common
o-the-shelf varieties of black, green, white, and oolong teas sold in tea bags were used for analysis in this study. Toxic element
testing was performed on  dierent teas by analyzing (i) tea leaves, (ii) tea steeped for - minutes, and (iii) tea steeped for –
minutes. Results were compared to existing preferred endpoints. Results. All brewed teas contained lead with % of teas brewed for
 minutes and % brewed for  minutes having lead levels considered unsafe for consumption during pregnancy and lactation.
Aluminum levels were above recommended guidelines in % of brewed teas. No mercury was found at detectable levels in any
brewed tea samples. Teas contained several benecial elements such as magnesium, calcium, potassium, and phosphorus. Of trace
minerals, only manganese levels were found to be excessive in some black teas. Conclusions. Toxic contamination by heavy metals
was found in most of the teas sampled. Some tea samples are considered unsafe. ere are no existing guidelines for routine testing
or reporting of toxicant levels in “naturally” occurring products. Public health warnings or industry regulation might be indicated
to protect consumer safety.
1. Introduction
edrinkingofteahasahistorythatlikelybeganinChina
more than  years ago. It has a relatively recent history in
the west beginning in the th century when it was introduced
to Portuguese priests and merchants. It became popular in
Britain in the th century. e use of tea bags was not
common until aer WWII.
Tea or i g inate s f r o m t he pl a n t Camellia sinensis,atreethat
maygrowuptofeetinheightunlesscultivated.Teaplants
require signicant rainfall of  inches a year and grow in
acidic soil. Contaminants may vary in the soil, air, or water in
which the plants are grown. Acidic soil may result in excess
available aluminum and uoride []. An acid or alkali soil
pH also enhances leaching of toxic heavy metals from the
soil []. Increasing pH with soluble calcium would reduce the
absorption of uoride []. Environmental pollutants such as
uoride and aluminum have been found in tea in part due to
the tea plants absorption and deposition and concentration
of these compounds in the leaves []. e drinking of more
than  liters of tea per week may result in dental or skeletal
uorosis []. Mercury, lead, arsenic, and cadmium as well
as other toxic elements have been found in tea leaves as
described in the literature [,]. Lead, arsenic, and cadmium
have also been found in brewed black tea []. ese soil and
air contaminants may be directly related to the use of coal
red power plants. e use of coal in China has increased
to . billion tons or about % of global coal consumption.
Coal burning power plants supply % of the energy in China
[]. Pollutants such as lead and mercury from power plants
are aecting the development of children, with lead resulting
in signicant decrease in social and average developmental
quotients [].
Teas are commonly grouped into  major categories:
white,yellow,green,oolong,andblacktea.Alloftheseare
readily available at most supermarkets in Canada except
yellow tea. For the purposes of this study common o the
shelfteaseitherorganicorregular(notlabeledasorganic)
Journal of Toxicology
were obtained as well as some that were available in health
food stores. All teas used were in tea bags used for brewing in
individual cups. e four types of tea sampled in this study
are white, green, oolong, and black tea.
Processingofdierenttypesofteasisasfollows.
() White tea: young leaves or new growth buds, with-
ered, uncured, baked dry;
() Green tea: steamed or dry cooking in hot pans to
prevent oxidation; dried tea leaves may be separate
leaves or rolled into pellets (gunpowder tea);
() Oolong tea: withering of leaves under sun and warm
winds with further oxidation standard between green
and black teas;
() Black tea: leaves are completely oxidized, withered,
anddisruptedormaceratedtoactivateoxidation
resulting in catechins being transformed to complex
tannins.
is study will look at some of the benets of tea as well
as the toxicants found in tea. e possible benecial and
medicinal aspects of tea as well as the detrimental eects of
heavy metals in tea are discussed below.
2. Medicinal Value of Green Tea
Green tea provides a small amount of magnesium, calcium,
potassium, phosphorus, and other trace elements considered
necessary for health. e results in our study are reported
below. Tea contains catechins, which are a type of antioxidant.
Whiteandgreenteashavethehighestconcentrationofthese
whileoolongandblackteashavelessduetotheoxidative
preparation. Tea also contains caeine which may vary from
 to  mg/cup depending on the type of tea and method of
brewing. Other medicinal ingredients are theobromine and
theophylline found in smaller quantities. ere are many and
varied eects of drinking tea which are outlined below.
2.1. Cardiovascular Eects. Many reports in the literature
suggest benet to the cardiovascular system by reducing
cholesterol, reducing coronary artery disease, ameliorating
hypertension, and inammation. Green tea has been shown
to reduce total and LDL cholesterol signicantly as shown in
a recent meta-analysis []. Total cholesterol was reduced by
. mg/dL and LDL by .mg/dL. A dose response curve
has been observed. Black tea has not been associated with
decreased risk of coronary artery disease, as outlined in a
recent meta-analysis, but there may be some benet from
green tea with a % risk reduction. However, more robust
studies are needed []. As well green tea may have some
antithrombotic eects [,]. A randomized control study
in obese hypertensive patients showed that green tea extract
may signicantly reduce hypertension (both systolic and
diastolic BP), insulin resistance, total and LDL cholesterol,
inammation, and levels of markers of oxidative stress [].
2.2. Anticancer Eects. ACochranereview()foundcon-
icting evidence that green tea drinking prevents cancer [].
More recent studies again show conicting results with
benet for some cancers but not for others. Green tea may
reduce risk in developing breast cancer. is eect has been
ascribed mostly to the phytochemicals which can modify
the metabolism of estrogens []. ese include polyphenols
(catechins) such as epigallocatechin gallate (EGCG), which
appears to be most potent, epigallocatechin, epicatechin
gallate, and epicatechin. Green tea drinking does not appear
to reduce the risk of developing prostate cancer and black tea
may increase prostate cancer risk [].Amostrecentmeta-
analysis shows that the consumption of green tea and coee
appearstoreduceesophagealcancerbutblackteadoesnot
[].
2.3. Weight Loss and Diabetes. ACochranereviewongreen
tea preparations []andweightlossshowedasmallnon-
signicant loss of weight in obese or overweight adults likely
notofclinicalrelevance.
In regard to diabetes green tea may result in lower fasting
glucose levels but no signicant HbAc changes []. ere
is some evidence that insulin resistance may be improved by
the antioxidant protective function of the polyphenols [].
As well there is evidence that these antioxidants may protect
the retina from neurodegenerative changes seen in diabetic
retinopathy [] and protect against nephropathy [].
2.4. Anti-Infective Properties. Green tea extract potentially
couldbeusedinamouthwashasapreventativefortooth
decay and periodontal disease because of its strong antibac-
terial properties []. Epigallocatechin gallate, the most active
component of green tea, has antiviral, antibacterial, and
antifungal properties [].
2.5. Miscellaneous Eects. Tea may reduce mercury absorp-
tion [,] and provide protection of nephrotoxicity [
].
e consumption of greater quantities of tea,  or more
cups compared to  or less, may provide some protection from
depression []. Another study in elderly patients suggests the
same [].
ere is some evidence that the polyphenols in green
tea may be protective against Alzheimer’s; however further
studies are required [].
3. Detrimental Effects of Heavy Metals in Tea
ere is an abundance of literature demonstrating the adverse
health eects of various heavy metal and metalloid ele-
ments on the human organism. By numerous mechanisms,
including endocrine disruption [], cytotoxicity [], mito-
chondrial dysfunction [], and oxidative stress [,], a
spectrum of toxic elements is able to disturb cellular and
metabolic homeostasis and induce clinical illness. e liter-
ature is replete with many common disease processes such
as carcinogenesis [], insulin resistance [], neurodegen-
eration [], and immune dysregulation [,]. ese may
result from exposure to and bioaccumulation of various
heavy metals and metalloids. In addition, recent literature has
Journal of Toxicology
elucidated that various toxic compounds can have epigenetic
eects with the potential for transgenerational damage [,
]. Rather than isolated incidents of single exposures, it is
apparent that toxic metal contact is a widespread phenome-
non [] with many potential sources including tainted food
anddrink,contaminatedskinproducts,andcontaminated
air. Many toxic metals such as cadmium and lead have very
long half-lives and thus are classied as persistent toxicants
[]. As some toxic elements appear to persist because
of enterohepatic recycling [,], even smaller levels of
exposure can bioaccumulate and eect long-term harm.
e toxic elements discussed in this paper include lead,
mercury, aluminum, and cadmium. e extremely low levels
of lead accepted in Proposition  during the prenatal period
come from our knowledge of the accumulation in the brain
and resultant impairment of cognitive development [,].
4. Methods
DistilledwaterwasanalyzedaerboilinginPyrexandthen
allowed to stand in ne bone china cup for  minutes. e
steeping of the teas was done in the ne china cups as might
be done in the real world.
All tea leaves were analyzed to determine the presence or
absence of metals.
All teas were steeped using one tea bag (containing - gm
of tea) in  mL of distilled water in ne bone china cups. All
teas had two samples taken, one steeped for - minutes and
another steeped for – minutes.
4.1. Sample Preparation for Analysis. Wat e r : s am p l es w e re
diluted -fold with .M HNO3(SP grade).
Liquids(watersandbrewedtea):sampleswerediluted-
fold with . M HNO3(SP grade).
Solids: approximately . g of sample was subjected to
closed-vessel MW-assisted digestion (MARS- oven,  W
 h holding time) using mL concentrated HNO3(SP grade),
. mL H2O2(PA grade) and . mL HF (SP grade). Aer
digestion, solutions were diluted with . M HNO3(SP grade)
providing nal dilution factor of approximately . A set
of digestion blanks and matrix-matched CRM were prepared
together with each digestion batch.
All solutions were spiked within (internal standard, at
𝜇g/L) and analyzed by ICP-SFMS (ELEMENT, ermo-
Scientic) using combination of internal standardization and
external calibration.
is analytical method is simple, ecient, and environ-
mentally friendly. e results in this study are consistent with
those found in other studies [].
5. Results
5.1. Minerals Found in Tea. In our study  cups of tea may
supply as much as % of daily calcium requirements, % of
magnesium requirements, -% of daily potassium require-
ments and –.% of phosphorus requirements using distilled
water. See Table . e use of regular tap water may provide
more magnesium, calcium potassium, and phosphorus than
using distilled water.
T : Healthy minerals found in teas in this study mg/L.
Calcium Daily minimum
requirement  mg
- minute steeping .–.
– minute steeping .–.
Magnesium Daily requirement
– mg
- minute steeping .–.
– minute steeping .–.
Potassium Daily requirements
– mg
- minute steeping –
– minute steeping –
Phosphorus Daily requirement
of  mg
- minute steeping .–.
– minute steeping .–.
Tracemineralsfoundinthebrewedteasamples
were boron – 𝜇gm/L, cobalt .–.𝜇gm/L, copper
– 𝜇gm/L, chromium .–. 𝜇gm/L, iron –
. 𝜇gm/L, manganese – 𝜇gm/L, molybdenum
.–. 𝜇gm/L, phosphorus – 𝜇gm/L, selenium
<.–. 𝜇gm/L, vanadium <.. 𝜇gm/L, and zinc
.–𝜇gm/L.
5.2. Heavy Metals in Tea. ere are established upper limits of
ingestion on a daily basis of heavy metals from various orga-
nizations. e most stringent are from Proposition  in Cal-
ifornia.
ese limits have been outlined in Tab l e  along with
other accepted limits.
e levels of toxic elements in this study for mercury
(Hg), lead (Pb), aluminum (Al), arsenic (As), and cadmium
(Cd) are outlined in Tab l e .
Of the  teas tested none had detectable levels of mercury
as brewed teas although / tea leaves had detectable
mercury present (as high as  ng/g of tea). It appears that
the mercury is bound in the leaf in a way that it does not
make its way into the brewed tea at levels that are detectable
(detectable limit in this assay is . 𝜇gm/L).
All teas contained signicant amounts of aluminum. Tea
leaves contained from  to  ng/g of tea. All brewed
teas steeped for  or  minutes contained detectable levels of
aluminum. e range was  𝜇gm/L to  𝜇gm/L steeping
for  minute and  𝜇gm/L to  𝜇gm/L steeping for 
minutes. Only  teas had levels above acceptable limits at 
minutes of brewing but  of the teas had levels greater than
the upper acceptable daily limit of  𝜇gm/L. C learly letting
tea steep for longer than  minutes is not advisable. Two of the
organicgreenteashadlevelsabove,𝜇gm/L brewed for
 minutes.
All brewed tea and tea leaves had detectable lead levels
with Chinese oolong teas having the highest levels, followed
by green tea and regular black tea having lower levels. Organic
Journal of Toxicology
T : Established toxicant limits in supplements (𝜇gm/day) adapted from [].
Tox ic element US California Proposition  (P)
and Environmental Protection Agency
European
union Australia World Health Organization Gestational limits
Mercury (Hg)  .
. inorganic
Hg
. methyl
Hg
. (methyl Hg in children) . for methyl Hg
Lead   NE 
Concern at low levels.
. established for
reproductive toxicity
(P)
Cadmium .   NE
Arsenic  . NE . NE
Aluminum , , , NE NE
NE: not established.
European/WHO/Australian levels were established by convention as representing % of the daily total toxicant intake aer conversion of values expressed in
mg/kg/week for an average adult weight of  kg.
T : Toxic element contaminants in teas.
TEAS Steeped - minutes Steeped – minutes
Ave rag e 𝜇g/LHgPbAlAsCdHgPbAlAsCd
Organic green
𝑁=10 None
detected
.
SD ±.
MX .

SD ±
MX 
.
SD ±.
MX .
.
SD ±.
MX .
None
detected
.
SD ±.
MX .

SD ±
MX 
.
SD ±.
MX .
.
SD ±.
MX .
Regular green
𝑁=7 None
detected
.
SD ±.
MX .

SD ±
MX 
.
SD ±.
MX .
.
SD ±.
MX .
None
detected
.
SD ±.
MX .

SD ±
MX 
.
SD ±.
MX .
.
SD ±.
MX .
Organic oolong
𝑁=2 None
detected . 
MX  . . None
detected
.
MX .

MX  . .
Standard oolong
𝑁=2 None
detected
.
MX .  . . None
detected
.
MX .  . .
Organic white
𝑁=3 None
detected
.
MX .  . . None
detected .  . .
Organic black
𝑁=1 None
detected .   None
detected
None
detected .  . None
detected
Standard black
𝑁=5 None
detected
.
MX .

MX  . . None
detected
.
MX .
.
MX  . .
SD is standard of deviation. None detected is below the limit of detection or <. ng/L and MX is maximum level detected.
whiteteashadthelowestleadlevel.Levelsrangedfrom
. 𝜇gm/L to . 𝜇gm/L aer subtracting the level found aer
brewing distilled water in ne china cups.
All brewed tea and tea leaves had detectable arsenic with
Chinese oolong teas (organic or regular) having the highest
levels. Levels in all teas ranged from . 𝜇gm to . 𝜇gm/L of
tea steeped for  minutes to . to . 𝜇gm/L of tea steeped
for  minutes.
All tea leaves had detectable levels of cadmium.  teas
had detectable levels aer  minutes brewing while only 
teas had detectable levels aer  minutes brewing suggesting
that there is further leaching of this toxicant into the water
over time. e highest level was . 𝜇gm/L found in
standard oolong tea from China.
All tea leaves and brewed teas had detectable levels of
cesium with one organic tea having  ng/g in the dry leaf,
. 𝜇gm/L at minutes of brewing and . 𝜇gm/L at 
minutes of brewing.
All tea leaves had detectable levels of tin but only two
brewed samples had nonsignicant levels detected in the teas.
All tea leaves and all teas had detectable levels of barium,
antimony and thallium but none had levels considered to be
of concern.
6. Discussion
Heavy metal contamination in tea has been described in the
literature before using the same method of analysis []. Lead
levels in the previous study were found to be the highest
in Chinese samples as seen in our study. Infusion for 
minutes increased the amount of toxicants in the previous
study similar to this study.
Journal of Toxicology
e benets of green tea as outlined above are multiple,
and tea may contribute to the daily intake of essential miner-
als and benet overall health. However, in the real world of
tea drinking it is important to look at several other factors to
minimize exposure to heavy metals.
First the source of tea and where it was grown (country of
origin) must be considered; see Tab l e  . It would be optimal to
drink tea with minimal exposure to toxicants in ground water,
soil, air, and rain. Second one must consider the water that
the tea is brewed with that may contain contaminants. Tap
water does contain more contaminants than distilled water.
ird the vessels that the water is boiled in may contribute
to toxicants and the cups either glass or ne china used for
steepingmayormaynotcontributetothetoxicload.In
this study the leaching of lead from the ne china cups into
distilled water alone resulted in a lead level of . 𝜇gm/L.
is was subtracted from all the analysis results of the teas
to obtain the true level contributed by the brewed tea.
Of the trace minerals manganese is the only mineral
found in substantial amounts in teas and some teas will supply
more than the total daily requirements. Black tea achieved
the highest level in this study. Excess manganese can result in
interference with the absorption of iron []andmayresult
in ADHD-like symptoms in children exposed in utero [].
In regard to toxic elements tested only aluminum and lead
had levels that were unacceptable. Unacceptable aluminum
levels were found in % of teas brewed for  minutes and
% of teas brewed for  minutes. e lead levels that were
present are a signicant concern during pregnancy in that
% of the samples brewed for  minutes and % of samples
brewed for  minutes were above . 𝜇gm/L. Despite smaller
amounts of cadmium and arsenic there is concern for long-
term bioaccumulation.
e organic teas had signicantly higher levels of lead
contamination if le steeping for more than  minutes than
the regular teas. Otherwise there was no signicant dierence
in levels of contaminants between organic teas and regular o
the shelf teas. Organic teas did not appear to have less toxic
element contamination than regular teas even from the same
company.
7. Limitations of the Study
A limitation of this study is that this is a sample of conve-
nience using samples readily available in supermarkets and
health food stores in Canada. is study did not look at u-
oride, which is a very common and signicant contaminant.
e particular method of analysis used here would not allow
for uoride analysis. e scope of this analysis did not look at
pesticides, herbicides, or other organic contaminants, which
are addressed in some of the organic labeling.
8. Recommendations Associated with
This Study
Although manganese is an essential trace mineral, levels in
black tea are quite high and may result in toxic levels when
adjusted for total daily intake from multiple sources.
e acceptable limit of lead in reproductive health is
. 𝜇gm on a daily basis. All but  teas or % of teas had
levels above this limit when consuming  cups of tea daily.
Consumption of tea needs to be severely limited during
pregnancy. e consumption of this and some prenatal
vitamins [] may easily exceed this daily limit and result
in signicant bioaccumulation over time especially in the
fetus. As well when the additional lead from the tea cup was
added, % of all teas had more than the acceptable limit of
lead.
eallowablelimitforleadingestionforadultsis𝜇gm
daily.Allbrewedteashaddetectablelevelsofleadabovethat
foundusingdistilledwaterinnechinateacupsandone
of the teas had . 𝜇gm/L of lead. Since tea is only part of
whatmaybeingestedonadailybasisthismaybesignicant.
Some nutritional supplements also have high levels of lead
especially Chinese and Ayurvedic herbal remedies []. In
combination it would be easy to exceed this daily limit. Chi-
nese oolong teas had the highest levels of lead and although
this is below the acceptable standard of  𝜇gm/day are best
avoided.
All teas had signicant levels of aluminum and  out of
 teas brewed for  minutes had unacceptably high levels.
Drinking more than  cups of tea a day may contribute sig-
nicantly to a toxic load.
Brewed tea appears to contain numerous toxic elements
such as arsenic and cadmium. However, none of these toxi-
cant levels were above present day acceptable standards.
Steeping tea for longer periods of time increases the
levels of these contaminants by  to % over steeping for 
minutes. erefore steeping for longer than  minutes should
be avoided.
Although mercury is found in the tea leaves no mercury
was detected in the brewed tea even when steeped for longer
periods of time. is raises an interesting question: would tea
be useful for detoxication from mercury?
e source of water used for brewing may contain some
contaminants and add to the toxic load.
One must know the manufacturing source and processing
of the cups in which the tea is brewed especially ne china
cups that may contain lead in the glaze. ere are manu-
factures that advertise having no lead glaze and glassware is
unlikely to have lead.
9. Conclusions
To move forward in diminishing the risk of toxic element
contamination a few points are oered for consideration.
When determining regulatory standards as well as individual
and public health recommendations, it is important to con-
sider the cumulative total load of toxic elements as some of
these agents including cadmium and lead have long half-lives
[] and constitute persistent pollutants within the human
body. As such, it is important to consider means to diminish
exposure as well as to facilitate elimination of toxic elements
from all sources, including beverages. Precautionary avoid-
ance is paramount as individuals and public ocials should
consider mechanisms to limit exposures that add to the total
burden. It is insucient to simply look at isolated exposures
Journal of Toxicology
T : Toxicant (heavy metal) levels according to country of origin.
Tea typ e Tea country of origin High levels Moderate levels Low levels
Green tea organic China Pb, Al As Cd
Green tea organic Sri Lanka Low in Pb, Cd, Al, As
Green tea organic Japan As, Pb, Cd, Al
Green tea standard China High in Al Pb, As Low in Cd
White tea India LowestinAl,Pb,Cd,As
White tea China Pb, Al, As Low in Cd
Oolong tea organic China HighestinAs,highinPb,Al LowinCd
Oolong tea standard China Highest in Pb Al, Cd, As
Black tea organic Blend India
Sri Lanka Al Pb Low in Cd, As
Black tea standard India
Sri Lanka Al Lowest Pb, low in Cd, As
Pb: lead, Cd: cadmium, Al: aluminum, As: arsenic.
to toxic elements, but rather to look at the total cumulative
exposure.
As such, if individuals are being exposed to lead, for
example, from drinking polluted tea as in this study, from
taking tainted supplements [], from consuming contami-
nated drinking water from lead pipes [], from eating or
drinking from dinnerware containing lead [], and so on,
the total daily exposure may be enormous. Simple regulation
to control the exposure from one source is insucient to
secure safety from toxic element bioaccumulation and thus
education in precautionary avoidance from all main sources
needs to be implemented.
Education to medical trainees about exposures to toxic
elements and persistent organic pollutants has been limited
in most medical centers thus far. Recognizing the escalating
problemoftoxicantbioaccumulation[], it would be pru-
dent to commence education of health professionals, inline
with recommendations from the World Health Organization
[] and other notable health bodies.
Public awareness campaigns may be eective in alerting
individuals to concerns related to toxic element bioaccumu-
lation and potential sources of exposure. Such awareness may
facilitate further avoidance as well as medical intervention to
eliminate accrued toxicants [].
In response to the Pediatric Academic Societies admoni-
tion that “low level exposure to environmental toxicity may
be impacting the functioning of the current generation,” []
education programs in schools may have some role in pro-
tecting and guiding developing children and their families.
Routine inspection and testing of foodstus and bever-
ages to rule out contamination—with results being made gen-
erally available—might identify compounds that are heavily
tainted and thus preclude contaminants from being con-
sumed. is might include a self-regulatory process that is
overseen by government ocials.
Original source labeling of products would provide con-
sumers with information about the geographic origins of
products. As some jurisdictions appear to have a greater prob-
lem with contamination [], this will give consumers choice
in their acquisitions and the opportunity to provide feedback
to jurisdictions which consistently demonstrate contamina-
tion.
Conflict of Interests
erearenoconictofinterests.
Authors’ Contributions
Gerry Schwalfenberg conceived and designed the experi-
ments. Gerry Schwalfenberg and Ilia Rodushkin performed
the experiments. Gerry Schwalfenberg and Stephen J. Genuis
analyzed the data. Gerry Schwalfenberg and ALS labs con-
tributed reagents/materials/analysis tools. Gerry Schwalfen-
berg, Stephen J. Genuis, and Ilia Rodushkin wrote the paper.
Acknowledgments
e authors would like to express gratitude to Cheryl
Schwalfenberg who carefully reviewed and edited this paper.
e rst author paid the fee for the toxicological testing at
ALS labs.
References
[] E. ´
Alvarez-Ayuso, A. Gim´
enez, and J. C. Ballesteros, “Fluoride
accumulation by plants grown in acid soils amended with ue
gas desulphurisation gypsum,Journal of Hazardous Materials,
vol.,no.,pp.,.
[] Z. Tan and G. Xiao, “Leaching characteristics of y ash from
Chinese medical waste incineration,Waste Management and
Research,vol.,no.,pp.,.
[] M. Fujimaki Hayacibara, C. S. Queiroz, C. P. Machado Tab-
choury, and J. Aparecido Cury, “Fluoride and aluminum in teas
and tea-based beverages,Revista de Saude Publica,vol.,no.
,pp.,.
[] S.-C. C. Lung, H.-W. Cheng, and C. B. Fu, “Potential exposure
and risk of uoride intakes from tea drinks produced in
Tai w a n ,” Journal of Exposure Science and Environmental Epi-
demiology, vol. , no. , pp. –, .
Journal of Toxicology
[] X.-P. Wang, Y.-J. Ma, and Y.-C. Xu, “Studies on contents of
arsenic, selenium, mercury and bismuth in tea samples col-
lected from dierent regions by atomic uorescence spectrom-
etry,Guang Pu Xue Yu Guang Pu Fen Xi,vol.,no.,pp.
, .
[] W.-Y. Han, F.-J. Zhao, Y.-Z. Shi, L.-F. Ma, and J.-Y. Ruan, “Scale
and causes of lead contamination in Chinese tea,Environmen-
tal Pollution,vol.,no.,pp.,.
[] S. Shekoohiyan, M. Ghoochani, A. Mohagheghian, A. H.
Mahvi, M. Yunesian, and S. Nazmara, “Determination of lead,
cadmium and arsenic in infusion tea cultivated in north of Iran,”
IranianJournalofEnvironmentalHealthScience&Engineering,
vol. , article , .
[] F. Perera, T.-Y. Li, Z.-J. Zhou et al., “Benets of reducing prenatal
exposure to coal-burning pollutants to childrens neurodevelop-
ment in China,Environmental Health Perspectives,vol.,no.
, pp. –, .
[] D.Tang,T.-Y.Li,J.J.Liuetal.,“Eectsofprenatalexposure
to coal-burning pollutants on children’s development in China,
EnvironmentalHealthPerspectives,vol.,no.,pp.,
.
[] X.-X. Zheng, Y.-L. Xu, S.-H. Li, X.-X. Liu, R. Hui, and X.-
H. Huang, “Green tea intake lowers fasting serum total and
LDL cholesterol in adults: a meta-analysis of  randomized
controlled trials,American Journal of Clinical Nutrition,vol.,
no. , pp. –, .
[] Z.-M. Wang, B. Zhou, Y.-S. Wang et al., “Black and green tea
consumption and the risk of coronary artery disease: a meta-
analysis,” AmericanJournalofClinicalNutrition,vol.,no.,
pp. –, .
[] M. Ali and M. Afzal, “A potent inhibitor of thrombin stimu-
lated platelet thromboxane formation from unprocessed tea,
Prostaglandins Leukotrienes and Medicine,vol.,no.,pp.
, .
[] W.-S. Kang, I.-H. Lim, D.-Y. Yuk et al., “Antithrombotic activ-
ities of green tea catechins and (-)-epigallocatechin gallate,
rombosis Research,vol.,no.,pp.,.
[] P. Bogdanski, J. Suliburska, M. Szulinska, M. Stepien, D.
Pupek-Musialik, and A. Jablecka, “Green tea extract reduces
blood pressure, inammatory biomarkers, and oxidative stress
and improves parameters associated with insulin resistance in
obese, hypertensive patients,Nutrition Research,vol.,pp.
–, .
[]K.Boehm,F.Borrelli,E.Ernstetal.,“Greentea(Camellia
sinensis) for the prevention of cancer,e Cochrane Database
of Systematic Reviews, no. , Article ID CD, .
[] B. J. Fuhrman, R. M. Pfeier, A. H. Wu et al., “Green tea intake is
associated with urinary estrogen proles in Japanese-American
women,Nutrition Journal, vol. , article , .
[] J. A. Montague, L. M. Butler, A. H. Wu et al., “Green and black
teaintakeinrelationtoprostatecancerriskamongSingapore
Chinese,Cancer Causes Control, vol. , pp. –, .
[] J. S. Zheng, J. Yang, Y. Q. Fu, T. Huang, Y. J. Huang, and D. L i,
“Eects of green tea, black tea, and coee consumption on the
risk of esophageal cancer: a systematic review and meta-analysis
of observational studies,Nutrition and Cancer,vol.,no.,pp.
–, .
[] T. M. Jurgens, A. M. Whelan, L. Killian, S. Doucette, S. Kirk,
and E. Foy, “Green tea for weight loss and weight maintenance
in overweight or obese adults,e Cochrane Database of Sys-
tematic Reviews,vol.,ArticleID,.
[] M. Maeda-Yamamoto, “Human clinical studies of tea polyphe-
nols in allergy or life style-related diseases,Current Pharma-
ceutical Design,vol.,no.,pp.,.
[] J.Yan,Y.Zhao,S.Suo,Y.Liu,andB.Zhao,“Greenteacatechins
ameliorate adipose insulin resistance by improving oxidative
stress,Free Radical Biology and Medicine,vol.,no.,pp.
–, .
[] K. C. Silva, M. A. Rosales, D. E. Hamassaki et al., “Green tea is
neuroprotective in diabetic retinopathy,Investigative O phthal-
mology & Visual Science,vol.,pp.,.
[]M.-Y.Kang,Y.H.Park,B.S.Kimetal.,“Preventiveeects
of green tea (Camellia Sinensis var. Assamica) on diabetic
nephropathy,” Yon s e i M e d i c a l J o u r n al,vol.,no.,pp.,
.
[] A. Araghizadeh, J. Kohanteb, and M. M. Fani, “Inhibitory activ-
ity of green tea (Camellia sinensis) extract on some clinically
isolated cariogenic and periodontopathic bacteria,Medical
Principles and Practice,vol.,no.,pp.,.
[] J. Steinmann, J. Buer, T. Pietschmann, and E. Steinmann, “Anti-
infective properties of epigallocatechin--gallate (EGCG), a
component of green tea,British Journal of Pharmacology,vol.
, pp. –, .
[]R.Canuel,S.B.deGrosbois,M.Lucotte,L.Atikess
´
e, C.
Larose, and I. Rheault, “New evidence on the eects of tea
on mercury metabolism in humans,Archives of Environmental
and Occupational Health,vol.,no.,pp.,.
[] M. He and W.-X. Wang, “Factors aecting the bioaccessibility
of methylmercury in several marine sh species,” Journal of
Agricultural and Food Chemistry,vol.,no.,pp.,
.
[]W.Liu,Z.Xu,H.Yang,Y.Deng,B.Xu,andY.Wei,“e
protective eects of tea polyphenols and schisandrin B on
nephrotoxicity of mercury,” Biological Trace Element Research,
vol. , no. , pp. –, .
[] O. Ou´
edraogo and M. Amyot, “Eects of various cooking
methods and food components on bioaccessibility of mercury
from sh,Environmental Research, vol. , no. , pp. –,
.
[] “Tea and coee with your sh?” Har vard Health Letter,vol.,
no.,article,.
[] N.M.Pham,A.Nanri,K.Kurotanietal.,“Greenteaandcoee
consumption is inversely associated with depressive symptoms
in a Japanese working population,” Public Health Nutrition,
.
[] K. Niu, A. Hozawa, S. Kuriyama et al., “Green tea consumption
is associated with depressive symptoms in the elderly,”American
Journal of Clinical Nutrition,vol.,no.,pp.,.
[] S. Davinelli, N. Sapere, D. Zella, R. Bracale, M. Intrieri, and G.
Scapagnini, “Pleiotropic protective eects of phytochemicals in
Alzheimer’s dise ase,Oxidative Medicine and Cellular Longevity,
vol.,ArticleID,pages,.
[] World Health Organization, “Global assessment of the state-of-
the-science of endocrine disruptors,” Geneva, Switzerland, pp.
–,  .
[] Y.W.Chen,C.F.Huang,C.Y.Yang,C.C.Yen,K.S.Tsai,and
S. H. Liu, “Inorganic mercury causes pancreatic 𝛽-cell death via
the oxidative stress-induced apoptotic and necrotic pathways,”
Toxicology and Applied Pharmacology,vol.,no.,pp.
, .
[] E. A. Belyaeva, T. V. Sokolova, L. V. Emelyanova, and I. O.
Zakharova, “Mitochondrial electron transport chain in heavy
Journal of Toxicology
metal-induced neurotoxicity: eects of cadmium, mercury, and
copper,e Scientic World Journal,vol.,ArticleID
,pages,.
[] L.Hu,J.B.Greer,H.Solo-Gabriele,L.A.Fieber,andY.Cai,
Arsenic toxicity in the human nerve cell line SK-N-SH in the
presence of chromium and copper,Chemosphere,vol.,no.,
pp.,.
[] M. Valko, H. Morris, and M. T. D. Cronin, “Metals, toxicity and
oxidative stress,Current Medicinal Chemistry,vol.,no.,pp.
–, .
[] A. R. Nair, O. Degheselle, K. Smeets, E. Van Kerkhove, and A.
Cuypers, “Cadmium-induced pathologies: where is the oxida-
tive balance lost (or not)?” International Journal of Molecular
Sciences,vol.,no.,pp.,.
[] N. F. Kolachi, T. G. Kazi, H. I. Afridi et al., “Status of toxic metals
in biological samples of diabetic mothers and their neonates,
Biological Trace Element Research,vol.,no.,pp.,
.
[] K. Jomova, D. Vondrakova, M. Lawson, and M. Valko, “Metals,
oxidative stress and neurodegenerative disorders,” Molecular
and Cellular Biochemistry,vol.,no.-,pp.,.
[] S. J. Genuis, “Sensitivity-related illness: the escalating pandemic
of allergy, food intolerance and chemical sensitivity,e S cience
of the Total Environment,vol.,no.,pp.,.
[] P. Moszczy´
nski, J. Rutowski, S. Słowi´
nski, and S. Bem, “Immu-
nological eects of occupational exposure to metallic mercury
in the population of T-cells and NK-cells,Analyst,vol.,no.
, pp. –, .
[] C. Guerrero-Bosagna and M. K. Skinner, “Environmentally
induced epigenetic transgenerational inheritance of phenotype
and disease,” Molecular and Cellular Endocrinology,vol.,no.
-,pp.,.
[] M. K. Skinner, “Role of epigenetics in developmental biology
and transgenerational inheritance,Birth Defects Research C,
vol.,no.,pp.,.
[] M. E. Sears, K. J. Kerr, and R. I. Bray, “Arsenic, cadmium,
lead, and mercury in sweat: a systematic review,Journal of
Environmental and Public Health, vol. , Article ID ,
 pages, .
[] M. E. Sears and S. J. Genuis, “Environmental determinants of
chronic disease and medical approaches: recognition, avoid-
ance, supportive therapy, and detoxication,Journal of Envi-
ronmental and Public Health,vol.,ArticleID,
pages, .
[] S. J. Genuis, “Elimination of persistent toxicants from the
human body,Human and Experimental Toxicology,vol.,no.
, pp. –, .
[] T. W. Clarkson, “Factors involved in heavy metal poisoning,
Federation Proceedings,vol.,no.,pp.,.
[] T. I. Lidsky and J. S. Schneider, “Lead neurotoxicity in children:
basic mechanisms and clinical correlates,Brain,vol.,no.,
pp. –, .
[]S.J.Genuis,G.Schwalfenberg,A.K.Siy,andI.Rodushkin,
“Toxic element contamination of natural health products and
pharmaceutical preparations,PLoS One, vol. , no. , Article
ID e, .
[] M.A.Rahman,B.Rahman,andN.Ahmed,“Highbloodman-
ganese in iron-decient children in Karachi,Public Health
Nutrition,vol.,no.,pp.,.
[] F. M. Crinella, “Does soy-based infant formula cause ADHD?
Update and public policy considerations,Expert Review of
Neurotherapeutics,vol.,no.,pp.,.
[] Y. Wang, H. Jing, V. Mehta, G. J. Welter, and D. E. Giammar,
Impactofgalvaniccorrosiononleadreleasefromagedlead
service lines,Wa t e r R e s e a rch, vol. , pp. –, .
[] R. W. Shee ts, “Release of heavy m etals from European and Asian
porcelain dinnerware,e Science of the Total Environment,vol.
, no. -, pp. –, .
[] Centers for Disease Control, Department of Health and Human
Services, “Fourth National Report on Human Exposure to
Environmental Chemicals,” Atlanta, Ga, USA, pp.–, ,
http://www.cdc.gov/exposurereport/pdf/FourthReport.pdf.
[] World Health Organization, “Children’s Health and the Envi-
ronment. WHO Training Package for the Health Sector,” World
Health Organization, , http://www.who.int/ceh/en/.
[] D. Coury, “Biological inuences on brain and behavior,” in
Proceedings of the Pediatric Academic Societies’ Annual Meeting:
Adolescent Medicine,Baltimore,Md,USA,.
... Cobalt, lead, cadmium are also reported but their presence is dependent on soil (Li and Wang 2009). Consumption of tea leaves beverage fulfils the daily requirement of essential minerals and Tea leaves are good source of potassium, manganese with positive effect on high blood pressure patients (Schwalfenberg et al. 2013;Fernandez et al. 2002). The content of minerals are more abundant in flowers than leaves (Muhlemann et al. 2012). ...
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The food industry is generating huge amounts of by-products, about 1,890,000 tons, which should be better recycled into pharmaceuticals, cosmetics and functional foods, for instance, in order to save costs and avoid pollution. Here we review food by-products and methods of extraction. We present bioactive compounds from fruits, vegetable, tea, coffee, egg, nuts, meat and dairy products. Extracting methods include soxhlet, maceration, microwave, ultrasound, pressure.
... Cobalt, lead, cadmium are also reported but their presence is dependent on soil (Li and Wang 2009). Consumption of tea leaves beverage fulfils the daily requirement of essential minerals and Tea leaves are good source of potassium, manganese with positive effect on high blood pressure patients (Schwalfenberg et al. 2013;Fernandez et al. 2002). The content of minerals are more abundant in flowers than leaves (Muhlemann et al. 2012). ...
... According to European commission contaminates like aluminium, mercury, chromium, lead, nickel, cadmium and arsenic are found in tea leaves [201][202][203][204] The tea contamination with heavy metals are atmospheric deposition, soil, applications of organic and chemical fertilisers, irrigation with polluted water, and waste disposal. ...
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... Tea polyphenols also help to prevent mutations in genetic materials, regulate detoxification enzyme activities, and inhibit tumorigenesis. Tea leaves have been used to produce tea infusions, and there are many types of tea products depending on the degree of oxidation processes, such as white tea (young tea leaves or new growth buds, withered, uncured, baked dry), green tea (no oxidized), oolong tea (partially oxidized), black tea or red tea (fully oxidized) (Han, Mihara, Hashimoto, & Fujino, 2014;Schwalfenberg, Genuis, & Rodushkin, 2013). Thanks to the development of analytical chemistry, we now know better various metabolites, in particular catechins, contributing to the antioxidant capacities. ...
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