The Facts Behind Teflon®
by Elizabeth Walterscheid
Kathleen Esquibel
Kelly Morgese
Jonathan Lucero
Page 1
Introduction
Teflon® is a component of many consumer products, such as non-stick
cookware, food wrappers, clothing, etc. The chemical components of
Teflon® are the source of much controversy because we encounter these
chemicals in our everyday life.
The chemical name for Teflon® is polytetrafluoroethylene (PTFE), other
chemical components include perfluorooctanoic acid (PFOA) and
perfluorooctane sulfonate (PFOS). These chemicals have been linked to
multiple aliments in animals, including death, and can have potential
damage to humans and the environment.
In this presentation, we will examine the toxic effects of the chemicals
composing Teflon®, specifically PTFE, PFOA, and PFOS, and their
impact on the world. We will explore the history of Teflon® and the
current political controversy surrounding its use; the chemicals structures
and properties; the mechanism of action; its impact on animals, wildlife,
and humans; the environmental impacts; and finally opposing research.
Page 2
Background
History:
• PTFE was accidentally invented by Roy Plunkett of DuPont Research
Laboratories in 1938. Plunkett was attempting to make a new CFC refrigerant,
however, the perfluorethylene polymerized in its pressurized storage container
and formed a white waxy solid, PTFE. They patented this product under the
name Teflon® (about.com).
• In 1954, PTFE was first used as a coating on cookware (wikipedia.com)
• PTFE, PFOA, and PFOS have since been used in numerous consumer
products
Page 3
Background
Politics:
•
EPA involvement
• The EPA has proposed a “PFOA stewardship” to phase out the production of
PFOA. By 2010, there will be a 95% reduction in the production of PFOA and
eliminated in 2015 (webmd.com).
• EPA fined DuPont $16.2 million dollars for not releasing the potential hazards
of the chemicals involved in their products (ewg.org).
• DuPont’s stance
• DuPont is complying with the stewardship and say they will work cooperatively
with the EPA. However, they still stand by their products (DuPont.com).
• Environmental Working Group
• Non-profit research program that presented the EPA with the toxic effects of
PFOA and other chemicals involved in Teflon® (ewg.org)
Page 4
Chemical Properties
Polytetrafluroethylene (PTFE)
Properties
Thermal Properties
Melting Point: 327 degrees Celsius
Surface Temperature: 260 degrees
Celsius
Heat of Combustion: 5.1MJ/kg
PTFE
•
•
•
a resin polymer that consists of
repeating tetrafluoroethylene
monomer units
resistant to many chemicals such
as ozone, ammonia, sulfuric acid
and hydrochloric acid
also contains weather and UV
resistant properties
Density: 2200 kg/m3
State: solid at room temp
• can be a powder
• can be in gas phase
• exists in liquid phase
Specific Gravity:2.132.22
Coefficient of Friction:
0.1
Impact Strength: 189
J/m
Tensile Strength: 21-35
Mpa
Page 5
Chemical Properties
Perfluoroctanoic Acid (PFOA)
PFOA
Molecular Formula: C8HF15O2
Density: 1.8g/cm3
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Melting Point: 40- 50 degrees Celsius
State: colorless liquid
•
Contains a hydrophilic head and a hydrophobic tail
•
PFOA can lower the surface tension of water
•
Found in PTFE and is produced by electrochemical fluorination
Page 6
Chemical Properties
Perfluoroctane Sulfonate (PFOS)
PFOS
Molecular Formula: C8HF17O3S
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Molar Mass: 500.13g/mol
Boiling Point: 133 degrees Celsius
•
Also made through electrochemical fluorination
•
Is a manmade global pollutant
•
Is a hydrophobic and lipophobic molecule
•
Can also lower the surface temperature of water
Page 7
Types of Teflon®
POLYTETRAFLUROETHYLENE
(PTFE)
Molecular Formula: Cn+F2n+2
• shows nearly universal chemical
resistance
• insoluble below 300 degrees
Celsius
• extremely hydrophobic
• very low adhesiveness
Fluorinated Ethylene Propylene
(FEP)
Molecular Formula: [CF(CF3)CF2(CF2-CF2)n]m
• copolymer of Tetraflouroethylene
and Hexafluoropropylene
• melting point of 260 degrees C
• density of 2150 kg/m3
• is thermoplastically moldable
• is translucent and flexible
Perfluoroalkoxy (PFA)
Molecular Formula: [(CF(OR)CF2(CF2-CF2)n]m
• translucent and slightly
flexible
• melting point of 305 degrees
C
• is more easily formable than
PTFE
Page 8
PerfluoroChemicals (PFOCs)
• Perfluorochemicals: are manmade that are used to make
products resistant to heat, oil, stains, grease and water.
These chemicals are found in the blood stream of many
animals including humans
• PFCs consist of a carbon backbone that is fully
surrounded by fluorine. The toxicokinetic aspects of these
PFCs are still unclear in humans. It has been shown that
females that are menstruating have higher concentrations
of PFOA and PFOS in their blood stream (Harada).
• Are very stable products that are not broken down in the
environment and can move long distances by way of
water.
Page 9
PerfluoroChemicals (PFOCs)
•
PFCs cause change in organ
weight leading to decrease
organ function
•
Have medical applications in
eye surgeries and artificial
blood
•
PFCs have chemical
inertness and thermal stability
•
Have a lifespan of up to
50,000 years in the
environment
Page 10
Mechanism of Action
Routes of Exposure:
 The toxic chemicals found within Teflon®, specifically PFOA, can have many
•
•
different routes of exposure (EWG.org). For instance:
• consumer products
• water
• food
• the environment
The chemicals found in the non-stick cookware made by Teflon® are released once
the cookware reaches a specific temperature.
• The chemicals become volatile gases and can enter the human lungs from
inhalation.
• By entering the lungs, these toxic chemicals bypass the First Pass Effect,
allowing them to build up in the blood.
PFOA contained in consumer products, such as food wrappers, enters the body by
absorption. The PFOA is absorbed from the wrapper by the food, when the food in
ingested, the small intestine first absorbs the chemical (EWG.org).
• The chemicals endure the First Pass Effect leading to a diminished toxic
effect, however, the toxin can still be found in the blood.
Page 11
Mechanism of Action
 Once in the human body, the exact mechanism is still unknown.
 Several studies have been conducted to examine the damage
PFOAs can have on the human body and to further understand
the mechanism. Some of those studies include:
 Effects on vital cell components
• Genotoxic effects of PFOA on human cells
Page 12
Mechanism of Action
Effects on Vital Cell Components:
 A study conducted by Konrad Kleszczynski and Andrzej C. Skladanowski examined
the alteration of plasma membrane potentials and intracellular pH in the presence
of PFAs. The basis of their study was to understand the mechanism in which PFAs
acted upon human cells. They conducted their study on human colon carcinoma
cells and measured the alterations by staining the cells. They chose to study two
important aspects of a cell:
• The plasma membrane is responsible for cell homeostasis, such as transport,
signal transduction, and proton concentration. Any type of disruption in the
membrane effects the membrane fluidity and thus can be used as a
characteristic to observe in human diseases.
• The pH of a cell is another important component. A change in pH changes the
ionization states of polar amino acids residues within proteins. Therefore, any
slight deviation can render the enzymes inactive or change the protein
structure.
• The study concluded that the longer the carbon backbone of the PFA, the more it
altered the plasma membrane and pH. Therefore, the longer the carbon backbone,
the more the structure resembled fatty acids, and thus more lipohilic. Once the
toxin was inside the cell, it altered the membrane and increased the pH. The
increase in pH lead to acidification which lead to increased amounts of reactive
oxygen species and reduction of mitochondrial transmembrane potential
•
•
Therefore, the overall mechanism is still unknown, however
the toxins seem to be most effective when lipohilic and result
in alterations of the membrane and pH or cells.
(Kleszynski)
Page 13
Mechanism of Action
Genotoxic effects of PFOA on human cells:
• A study conducted by Xiaogeng Yao and Laifu Zhong examined
the toxic effects of PFOA on human hepatoma cells with emphasis
on genotoxic risk and oxidative DNA damage.
• From the previous study, it was stated that acidification lead to
increased amounts of reactive oxygen species (ROS)
(Kleazynski). This study takes that information and examines what
effect ROS have on the cells.
• The study concluded that the ROS that arose from
exposure to PFOA, lead to genotoxic effects.
• This was because the ROS targeted not only the bases but the
•
deoxyribose backbone and other cell components such as lipids
and peroxisomes. This lead to oxidative DNA damage, which is
believe to starting point for a mutagenic species.
(Yao)
Page 14
Mechanism of Action
• These two studies conclude that an essential part of the PFOA
mechanism in humans deals with:
• production of ROS which leads to
• oxidative DNA damage
• This damage may lead to a mutagenic cell, and possibly cancer
• And the longer the carbon backbone, the more readily it will enter
the cells and cause DNA damage due to the compounds
becoming more lipohilic.
Page 15
Hazards of Teflon®
“It is found everywhere from babies in the womb to whales in the
ocean”-- Kenneth Cook (president of Environmental Working
Group
•
•
•
•
Laboratory Studies:
PTFE(polytetrafluoroethylene) fumes in large numbers of
ultrafine particles can cause severe lung injury
Exposure to both the gas phase and ultrafine particles together
was needed to see a significant response from the rats
Pre exposure may allow for a lessened response from the
organism
Fumes toxic to rats when inhaled for only 15 minutes
(Johnston).
PFOA(perfluorooctanoic acid) was fed orally to a cohort of pregnant
mice for gestational term
•
mice fed 40 mg/kg of PFOA all resorbed their litters
•
other litters showed significantly lower birth weights
• Postnatal survival was greatly lowered in all groups
•
causes early pregnancy loss and general growth and
development problems in surviving offspring (Lau&Hansen).
•
PFOA is able to cross the placenta barrier readily
•
Even after administration of PFOA was done it still resided in
the breast milk exposing the young
Page 16
Hazards of Teflon®
•
In two to five minutes Teflon coated
cookware can exceed temperatures
that cause the coating to flake off
•
At 600 degrees C Teflon coated pans
emit a least six different volatile gases
including two different carcinogens.
•
According to a spokeswoman for the
Environmental Working Group based in
Washington D. C. “ Teflon is a likely
source of the PFOA that is measured in
people”
•
Makers of the product Teflon still claim
that products coated in Teflon are safe
however, have agreed to phase out the
use of PFOA by the year 2015
Page 17
Effects on Birds
“Teflon® Toxicity”
•
Both wild and domesticated birds are negatively effected
from Teflon. Studies show that birds suffer from inflamed
lungs and also enlarged livers due to inhalation of Teflon
gases.
•
Lungs become congested and often hemorrhage leaving
the bird gasping for air and eventually dying from
suffocation. Even mild exposure can cause wheezing,
weakness or even seizures in birds.
•
Birds are extremely efficient at gas exchange in order to
provide higher levels of oxygen for muscles during flight
which creates sensitivity and possible side effects when
breathing in toxic gases such as Teflon.
•
This toxicity affects all kinds of birds and the smaller the
bird the less fumes are required to effect it. When a bird is
displaying signals such as open mouth breathing it is
usually too late to save it.
Page 18
Effects on Wildlife
Teflon NEVER breaks down in the environment!
•
PFOA found in garbage littered in the water in things
such as: fast food wrappers, cosmetics, and household
cleaners
•
These perfluorochemicals cause cancer of the
pancreas, liver and breast and can also cause
reproductive defects.
•
PFCs (perfluorochemicals) have shown up in wildlife on
at least three continents and in the blood of animals
such as dolphins, seals, minks, polar bears, sea turtles
and bald eagles
•
The liver and blood tissues of wild animals are the
major accumulators of PFCs and studies show positive
correlations between levels of PFOA and PFOS in the
liver and blood of marine animals.
Page 19
Teflon® Toxicity in Humans
"Better things for better living -- through chemistry
.“ DuPont slogan
1940s-1980s
•
•
PFOA exposure is suggested to be associated with infertility in women
Exposure can cause irregular breathing, muscle incoordination, birth defects and
changes in the weight of newborn babies
• PFCs are found in the blood of nearly every person in the United States in
children as young as two, making the amount of PFCs in Americans greater than
any other country
• PFCs bioaccumulate in the human blood stream and have been suggested to
cause flu-like symptoms in humans and can stay in the body for years
• Research done by the EPA has shown that
three of the four tumors caused by PFOA is
rising, these include breast, liver, prostate &
testicular tumors
• PFOA is also shown in lab studies to cause
hypothyroidism & was also found in much
larger concentrations than even the lab animals
Page 20
Environmental Concerns
•
PFOAs are considered bioaccumulative, therefore, they can be
found all over the environment. For instance:
• Water: surface, rain, oceans
• Solids: soil, sediment, sludge
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Environmental Concerns
PFAs in Water:
Water samples have been taken from all over the world, and PFAs have been found in nearly every
sample from New York to Germany to Australia. For Instance:
• 9 major bodies of surface water in New York State have been tainted with PFOS and
PFOA. Birds and fish in those specific ecosystems also show levels of PFAs (Sinclair).
• A study conducted in Bayreuth Germany found that river water, which had waste water
feeding into it from a nearby waste treatment plant, contained PFOA and PFOS. These
chemicals were also found in fish species living in the river (Becker).
• A case study that examined the aquatic environment in Australia stated that, “besides
wastewater different other pathways as emissions from point sources, further degradation
of precursor products, runoff from contaminated sites or surface runoff as well as dry and
wet deposition have to be considered as relevant sources for PFAS contamination in
surface waters” (Clara, et.all., 4760)
• To study ocean water, water samples were taken from Northern Europe, Atlantic and
Southern Oceans. Each sample contained PFOAs and PFOSs, espeically in the North
and Mid Atlantic Oceans. This study concluded that PFAs are distributed throughout the
ocean primarily due to ocean sinks (Ahrens).
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Environmental Concerns
PFAs found in solids:
Although it has been highly recognized that PFAs have accumulated in
water, further studies have found the chemicals within solids.
•Soil, Sediment, and Sludge samples were collected in Shangi,
China. Each sample contained different levels of PFOA. The
samples of sludge contained the most (Li).
•Therefore, one could assume that PFAs are being readily absorbed
into the soils, as well as waters.
•When these chemicals are absorbed into the soil, primarily through
waste leaching into the soil from landfills, they can directly effect
humans by then absorbing into the plants and food that humans
consume (Ay).
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Environmental Concerns
Global Fate:
The fact that the chemicals involved in Teflon® are bioaccumulative, the
question that remains is what will happen over time if they continue to be
released into the environment.
• One particular study models this scenario. They concluded that that
• northern hemisphere was responsible for 15% of the global emission
• the ocean is a primary pathway for the transport of these chemicals.
• In time, Artic marine life will be greatly affected
• The more chemicals contained in the atmosphere, the greater effect on
terrestrial life.
• (Armitage).
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Oppositional Research
• Dupont, the creator of Teflon, had own safety
research conducted. The results of this
research declared:
• Cookware coated with Teflon is SAFE to use.
• Research concludes there have been ‘no record’ of any
‘significant’ human health problems.
• More than 2 billion pots and pans with Teflon coatings have been
purchased by consumers in over 40 countries worldwide.
• The ‘recommended’ maximum use temperature for cookware with
Teflon non-stick coating is 500°F (260°C).
• In 2003, the U.S. Consumer Product Safety Commission rejected
a petition to require a warning label for non stick coatings.
Page 25
Oppositional Research
DuPont claims: “Accidental Ingestion of Teflon® is Harmless”
• Particles from Teflon® branded cookware are not harmful, even if
ingested. Confidence in the safety and performance of DuPont nonstick coatings is based on more than 40 years of laboratory testing
and use in home and commercial kitchens.
• In rare instances, a person may accidentally ingest a flake of non-stick
coating from an aged pan. The coating flake is non-toxic and would
pass through the body without being absorbed. Based on the inert
characteristics of the coating, data indicates that there are no health
effects from the incidental ingestion of pieces of non-stick coating.
• Many companies use PFOA to produce a wide variety of products,
including auto fuel systems, clothes, computer chips, firefighting foam,
phone cables, as well as Teflon®.
Page 26
Oppositional Research
DuPont claims:” Many Benefits of Cooking With Teflon®”
•
Cooking with non-stick coated cookware allow for easy clean up and
ability to save time and effort washing pots and pans.
• The American Heart Association advises people to "use non-stick
cookware so you can cook with a minimum of oil or vegetable oil
spray" to help "create a healthier diet without losing out on flavor."
• Also, by limiting the amount of oil and fat in your cooking, you reduce
your risk of stovetop fires, the number one cause of house fires.
Page 27
Oppositional Research
Findings of Federal Agency Research
• The U.S. Environmental Protection Agency (EPA) “Does not believe
there is any reason for consumers to stop using any consumer or
industrial-related products” that are sold under the Teflon brand.
• The U.S. Food and Drug Administration (FDA) has found Teflon nonstick coatings acceptable for conventional kitchen use.
• Additional Research:
• As published in the Environmental Science & Technology journal,
ten researchers looked at the use of PFOA in cookware, as well as
carpets, cleaners, clothes, paints, and other products. They
concluded that PFOA exposure "during consumer use of the
articles evaluated in this study are not expected to cause adverse
human health effects in infants, children, adolescents, adult
residents or professionals, nor result in “quantifiable levels" of the
chemical in people's blood.
Page 28
Oppositional Research
Additional Research
• PFOA’s in Breast Milk: One study found that PFOA’s are passed from
mother to child sometimes as high as 0.27 micrograms/day for an
infant of 5 kg. This amount is still under the recommended
tolerable daily intake levels of PFOA’s. Additional research needs
to be conducted in order to identify amount and time-trend effects of
PFOA’s throughout pregnancy and after-delivery care.
• Contaminated Public Drinking Water: One study found there was no
significant difference between incidence of low birth weight, preterm
birth, mean birth weight and mean gestational age of neonates in
areas of different water categories.
• Kidney Transport of PFOA’s: One study found the half life of PFOA’s
in male rats is 70 times longer than in female mice. Sex hormone
levels played a significant role in amount of PFOA’s present in the
kidney.
Page 29
Discussion
• The research conducted in this presentation
informed us that the chemical makeup of Teflon®
is:
• Highly dangerous to animals, such as birds, rats and
marine life.
• Poses potential dangers to humans and fetuses.
• The chemicals are found in 95% of Americans blood.
• Bioaccumulative, it will always be in the environment
• It is found in our water, soil, and atmosphere.
• The “PFOA stewardship” started by the EPA will reduce future
accumulation.
• The mechanism of action involves reactive oxygen
species leading to DNA damage.
• However, DuPont believes that, even though their
products give off such chemicals, the level of exposure
is still below limits.
Page 30
Potential Remedies
Chemical manipulation
Possible non-toxic or non-volatile isomers (and enantiomers) could
potentially turn this useful but seemingly dangerous product into something
safe. In other words, organic chemists have some much needed research to
do as not too much research in this area (at least as a replacement for Teflon)
has been conducted. It could also be possible that “there is no free lunch”
with this one.
A promising non-toxic processing aids besides PFOAs is called PFHxA.
PFHxA is a six carbon molecule as opposed to 8 in PFOA/Ss and has
breakdown products that are supposedly much, much less toxic and don’t
have the same persistence issues that PFOA and some of the C8s have. It is
possible however that the chemical industry is trying to replace one toxic
chemical with another that may be just as toxic -- and calling it green
chemistry (www.thepanelist.net, Chengelis CP) .
Page 31
Potential Remedies
Elimination
•
Reduction of use plans-The good news is that the US Food and Drug
Administration has a voluntary agreement with several companies to phase
out PFOA production over the next few years. Also, an investigation into the
health effects of PFOA is underway in West Virginia, where thousands of
people have been exposed over decades after the chemical was released
from an industrial plant owned by the US manufacturer, DuPont. Tony
Fletcher, a scientist working on the investigation and an environmental
epidemiologist at the London School of Hygiene and Tropical Medicine, said a
full report is due next year (Mezler, D).
Page 32
Conclusion
•
It is important to monitor your usage of Teflon® products, and all other
products that contain PFOA and PFOS in order to reduce long term harmful
effects.
• It is important to find products that do not contain these chemicals in
order to reduce level of exposure and to stop the damage being done
to our environment.
•
Additional Research needs to be conducted to pinpoint the harmful effects of
PFOA’s on humans, however, there are various animal models that show
adverse side effects when testing with PFOA’s.
• However, the mutagenic effects of DNA when exposed to PFOA supports
the conclusion that exposure to these chemicals can be carcinogenic.
•
It is possible that animal models are not consistent with human toxicity levels,
but time-trend research will suggest harmful side effects of Teflon use.
Page 33
•
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