page 1 the facts behind teflon® by elizabeth walterscheid kathleen esquibel kelly morgese jonathan...

The Facts Behind Teflon®by Elizabeth Walterscheid Kathleen Esquibel Kelly Morgese Jonathan Lucero

IntroductionTeflon® 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.

BackgroundHistory:• 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

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)

Chemical PropertiesPolytetrafluroethylene (PTFE)

Thermal PropertiesMelting 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

PropertiesDensity: 2200 kg/m3

State: solid at room temp• can be a powder• can be in gas phase• exists in liquid phase

Specific Gravity:2.13-2.22

Coefficient of Friction: 0.1

Impact Strength: 189 J/m Tensile Strength: 21-35 Mpa

Chemical PropertiesPerfluoroctanoic Acid (PFOA)

PFOA

Molecular Formula: C8HF15O2

Density: 1.8g/cm3

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

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Chemical PropertiesPerfluoroctane Sulfonate (PFOS)

PFOSMolecular Formula: C8HF17O3S

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



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

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.

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

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.

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

Mechanism of ActionEffects 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)

Mechanism of ActionGenotoxic 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)

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.

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

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

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.

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.

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

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



Environmental ConcernsPFAs 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).



Environmental ConcernsPFAs 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).



Environmental ConcernsGlobal 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).



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.


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 non-stick 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®.


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.

Oppositional ResearchFindings 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 non-stick 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.

Oppositional ResearchAdditional 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.

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.

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) .

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).

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.

References • Ahrens, L., et.all. Distribution of perfluoroalkyl compounds in seawater from Northern Europe, Atlantic Ocean,

and Southern Ocean.Chemosphere 78 (2010) 1011- 1016. • Armitage, A., et. All. Comparative Assessment of the Global Fate and Transport pathways of Long-Chain

Perflurocarboxylic Acids (PFCAs) and Perflurocarboxylates (PFCs) Emmitted From Direct Sources . Environ. Sci. Technol 43 (2009) 5830-5836.

• Ay, L., et. All. Waste management to improve food safety and security for health advancement. Asian Pacific Journal of Clinical Nutrition 18 (2009) 538- 545.

• Becker, A. Gertsmann, S., Frank,H. Perfluorooctanoic Acid and Perfluorooctane Sulfonate in Two Fish Species Collected from the Roter Main River, Bayreuth, Germany. Environmental Contamination and Toxicology 84 (2010) 132-135.

• DuPont. Teflon: Safety of Teflon Non-Sticks. 2010. March 31, 2010. http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html

• Giesy, J., Kannan, K. “ Perfluorochemical Surfactants in the Environment” Environmental Science and Techonology. (2002) Vol. 36(7):146A-152A.

• Giesy, J., Kannan, K. “ Global Distribution and Bioaccumulation of Perfluorinated Hydrocarbons” National Food Safety and Toxicology Center (2002) Vol. 59.

• Harada,et.all. “ Renal clearance of perfluorooctane sulfonate in humans and their species specific excretion” Environmental Research Vol. 99(2):253-261.

• Johnston, C.J.,et. all.. “Pulmonary Effects induced by ultrafine PTFE particles” Toxicology AppliedPharmacolgy. Vol. 168(3):208-215.

• Kannan, K., et. all. “ Concentration of PFOA in livers of birds from Japan to Korea” Chemosphere (2002) Vol. 49(3):225-231.

• Kleszczynski, K., Skladanowski, A.C. Mechanism of cytotoxic action of perfluorinated acids. I. Alteration in plasma membrane potential and intracellular pH level. Toxicology and Applied Pharmacology 234 (2009) 300-305.

• Kudo, N., Katakura, M., Sato, Y., and Kawashima, Y. 2002. Sex Hormone-Regulated Renal Transport of Perfluorooctananoic Acid. Chemico-Biological Interactions. Vol. 139: 301- 316.

References • Li, F., et. All. Quantitative characterization of short- and long-chain perfluorinated acids in solid matrices in

Shanghai, China. Science of the Total Environment 408 (2010) 617-623.• Lau,C. et. all. “Effects of Perfluoroocatanoic Acid Exposure During Pregnancy in the Mouse” Toxicological

Sciences (2006) Vol.90(2):10-518.• Nolan, L., Nolan, J., Shofer, F., Rodway, N., and Emmett, E. 2008. The Relationship between Birth Weight,

Gestational Age and Perfluorooctanoic Acid (PFOA)-contaminated public drinking water. Reproductive Toxicology. Vol. 27: 231- 238.

• Perfluorinated Compounds and Human Health Concerns. www.Globalhealthsafety.org.• Polytetrafluoroethylene. en.wikipedia.org/wiki/Polytetrafluoroethylene.• Sinclair, E., et. all. Occurrence of Perfluoroalkyl Surfactants in Water, Fish, and Birds from New York State.

Environmental Contamination and Toxicology 50 (2006) 398-410.• Teflon- PFOA www.ewg.org.• The Invention of Teflon- Roy Plunkett. inventors.about.com/library/inventors/blteflon.htm.• Volkel, W., Genzel-Boroviczeny, O., Demmelmair, H., Gebauer, C., Koletzko, B., Twardella, D., Raab, U., and

Fromme, H. 2007. Perfluorooctane Sulphonate (PFOS) and Perfluorooctanoic Acid (PFOA) in human breast milk: Results of a Pilot Study. Environ-Health. Vol. 211: 440- 446.

• Yao, X., Zhong, L. Genotoxic risk and oxidative DNA damage in HepG2 cells exposed to perfluorooctanoic acid. Mutation Research 587 (2005) 38-44.

page 1 the facts behind teflon® by elizabeth walterscheid kathleen esquibel kelly morgese jonathan...

Documents

pfoa stewardship

production of pfoa

perfluorooctanoic acid

chemical components

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polytetrafluoroethylene

history of teflon

toxic effects of pfoa