Perfluorooctanoic acid: Difference between revisions

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| MolarMass = 414.07 g/mol
| MolarMass = 414.07 g/mol
| Appearance = colorless liquid
| Appearance = colorless liquid
| Density = 1.8 g/cm<sup>3</sup> <ref name="GESTIS">{{GESTIS|ZVG=493012|CAS=335-67-1|Name=Perfluorooctanoic acid|Date=5 November 2008}}</ref>
| Density = 1.8 g/cm<sup>3</sup> <ref name=GESTIS>{{GESTIS|ZVG=493012|CAS=335-67-1|Name=Perfluorooctanoic acid|Date=5 November 2008}}</ref>
| Solubility = soluble, 3.4 g/L (PFO)<ref name="GESTIS"/>
| Solubility = soluble, 3.4 g/L (PFO)<ref name=GESTIS/>
| Solvent = other solvents
| Solvent = other solvents
| SolubleOther = polar organic</br> solvents
| SolubleOther = polar organic</br> solvents
| MeltingPt = 40–50 °C <ref name="GESTIS"/>
| MeltingPt = 40–50 °C <ref name=GESTIS/>
| BoilingPt = 189–192 °C <ref name="GESTIS"/>
| BoilingPt = 189–192 °C <ref name=GESTIS/>
| pKa = 0
| pKa = 0
| Viscosity =
| Viscosity =
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}}
}}
| Section7 = {{Chembox Hazards
| Section7 = {{Chembox Hazards
| ExternalMSDS = <ref name="GESTIS"/>
| ExternalMSDS = <ref name=GESTIS/>
| MainHazards = Strong Acid, Causes Burns
| MainHazards = Strong Acid, Causes Burns
| RPhrases = {{R22}} {{R34}} {{R52/53}}
| RPhrases = {{R22}} {{R34}} {{R52/53}}
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==History==
==History==
In [[1947]], [[3M]] began producing PFOA by the electrochemical fluorination method.<ref name="Prevedouros2006">{{cite journal |author=Prevedouros K, Cousins IT, Buck RC, Korzeniowski SH |title=Sources, fate and transport of perfluorocarboxylates |journal=Environ Sci Technol. |volume=40 |issue=1 |pages=32–44 |year=2006 |month=Jan |pmid=16433330 }}</ref> In [[1951]], [[DuPont]] started using PFOA in the manufacturing of [[fluoropolymers]] in [[Washington, WV]].<ref name="Emmett2006">{{cite journal |author=Emmett EA, Shofer FS, Zhang H, Freeman D, Desai C, Shaw LM |title=Community exposure to perfluorooctanoate: relationships between serum concentrations and exposure sources |journal=J Occup Environ Med. |volume=48 |issue=8 |pages=759–70 |year=2006 |month=Aug |pmid=16902368 |doi=10.1097/01.jom.0000232486.07658.74 }}</ref> In [[1961]], DuPont was aware of [[hepatomegaly]] in mice fed PFOA.<ref>Gerald J. Arneson: [http://www.defendingscience.org/case_studies/upload/1961-memo.pdf "Toxicity of Teflon Dispersing Agents"] DuPont, Polychemicals Department, Research & Development Division, Experimental Station, (November 9, 1961). Accessed September 21, 2008.</ref><ref name="Clapp">Clapp, Richard; Hoppin, Polly; Jagai, Jyotsna; Donahue, Sara: [http://www.defendingscience.org/case_studies/perfluorooctanoic-acid.cfm "Case Studies in Science Policy: Perfluorooctanoic Acid"] Project on Scientific Knowledge and Public Policy (SKAPP). Accessed September 21, 2008.</ref> In [[1968]], [[organofluorine]] content was detected in the [[blood serum]] of consumers, and in [[1976]] it was suggested to likely be PFOA.<ref name="Kennedy2004">{{cite journal |author=Kennedy GL, Butenhoff JL, Olsen GW, ''et al'' |title=The toxicology of perfluorooctanoate |journal=Crit Rev Toxicol. |volume=34 |issue=4 |pages=351–84 |year=2004 |pmid=15328768 }}</ref> In [[1980]], PFOA was identified as the primary organofluorine present in the blood serum of fluorochemical production workers.<ref>{{cite journal |author=Ubel FA, Sorenson SD, Roach DE |title=Health status of plant workers exposed to fluorochemicals--a preliminary report |journal=Am Ind Hyg Assoc J |volume=41 |issue=8 |pages=584–9 |year=1980 |month=Aug |pmid=7405826 }}</ref> In the 1980s and 1990s researchers investigated the [[toxicity]] of PFOA. In [[1999]], the [[USEPA]] began investigating perfluorinated chemicals after receiving data on the global distribution and toxicity of [[PFOS]].<ref>Aziz Ullah. [https://www.restorationindustry.org/buyersguide/FlurochemicalsOct06.pdf "The Fluorochemical Dilemma: What the PFOS/PFOA fuss is all about"] Cleaning & Restoration. www.ascr.org, (October, 2006). Accessed September 24, 2008.</ref> For these reasons, in [[May]] of [[2000]], 3M announced the phaseout of the production of PFOA, PFOS, and PFOS-related products.<ref name="3M08">3M: [http://solutions.3m.com/wps/portal/3M/en_US/PFOS/PFOA/Information/Action/ "PFOS-PFOA Information: What is 3M Doing?"] Accessed September 22, 2008.</ref> After the PFOA-phaseout by 3M, increased attention has been directed towards PFOA, DuPont, and the USEPA, as described below. Additionally, advances in [[analytical chemistry]] in recent years have allowed the routine detection of low- and sub-[[parts per billion|ppb]] levels of PFOA in water, food, wildlife, and humans.<ref>{{cite journal |author=Lau C, Butenhoff JL, Rogers JM |title=The developmental toxicity of perfluoroalkyl acids and their derivatives |journal=Toxicol Appl Pharmacol. |volume=198 |issue=2 |pages=231–41 |year=2004 |month=Jul |pmid=15236955 |doi=10.1016/j.taap.2003.11.031 }}</ref>
In [[1947]], [[3M]] began producing PFOA by the electrochemical fluorination method.<ref name=Prevedouros2006>{{cite journal |author=Prevedouros K, Cousins IT, Buck RC, Korzeniowski SH |title=Sources, fate and transport of perfluorocarboxylates |journal=Environ Sci Technol. |volume=40 |issue=1 |pages=32–44 |year=2006 |month=Jan |pmid=16433330 }}</ref> In [[1951]], [[DuPont]] started using PFOA in the manufacturing of [[fluoropolymers]] in [[Washington, WV]].<ref name=Emmett2006>{{cite journal |author=Emmett EA, Shofer FS, Zhang H, Freeman D, Desai C, Shaw LM |title=Community exposure to perfluorooctanoate: relationships between serum concentrations and exposure sources |journal=J Occup Environ Med. |volume=48 |issue=8 |pages=759–70 |year=2006 |month=Aug |pmid=16902368 |doi=10.1097/01.jom.0000232486.07658.74 }}</ref> In [[1961]], DuPont was aware of [[hepatomegaly]] in mice fed PFOA.<ref>Gerald J. Arneson: [http://www.defendingscience.org/case_studies/upload/1961-memo.pdf "Toxicity of Teflon Dispersing Agents"] DuPont, Polychemicals Department, Research & Development Division, Experimental Station, (November 9, 1961). Accessed September 21, 2008.</ref><ref name=Clapp>Clapp, Richard; Hoppin, Polly; Jagai, Jyotsna; Donahue, Sara: [http://www.defendingscience.org/case_studies/perfluorooctanoic-acid.cfm "Case Studies in Science Policy: Perfluorooctanoic Acid"] Project on Scientific Knowledge and Public Policy (SKAPP). Accessed September 21, 2008.</ref> In [[1968]], [[organofluorine]] content was detected in the [[blood serum]] of consumers, and in [[1976]] it was suggested to likely be PFOA.<ref name=Kennedy2004>{{cite journal |author=Kennedy GL, Butenhoff JL, Olsen GW, ''et al'' |title=The toxicology of perfluorooctanoate |journal=Crit Rev Toxicol. |volume=34 |issue=4 |pages=351–84 |year=2004 |pmid=15328768 }}</ref> In [[1980]], PFOA was identified as the primary organofluorine present in the blood serum of fluorochemical production workers.<ref>{{cite journal |author=Ubel FA, Sorenson SD, Roach DE |title=Health status of plant workers exposed to fluorochemicals--a preliminary report |journal=Am Ind Hyg Assoc J |volume=41 |issue=8 |pages=584–9 |year=1980 |month=Aug |pmid=7405826 }}</ref> In the 1980s and 1990s researchers investigated the [[toxicity]] of PFOA. In [[1999]], the [[USEPA]] began investigating perfluorinated chemicals after receiving data on the global distribution and toxicity of [[PFOS]].<ref>Aziz Ullah. [https://www.restorationindustry.org/buyersguide/FlurochemicalsOct06.pdf "The Fluorochemical Dilemma: What the PFOS/PFOA fuss is all about"] Cleaning & Restoration. www.ascr.org, (October, 2006). Accessed September 24, 2008.</ref> For these reasons, in [[May]] of [[2000]], 3M announced the phaseout of the production of PFOA, PFOS, and PFOS-related products.<ref name=3M08>3M: [http://solutions.3m.com/wps/portal/3M/en_US/PFOS/PFOA/Information/Action/ "PFOS-PFOA Information: What is 3M Doing?"] Accessed September 22, 2008.</ref> After the PFOA-phaseout by 3M, increased attention has been directed towards PFOA, DuPont, and the USEPA, as described below. Additionally, advances in [[analytical chemistry]] in recent years have allowed the routine detection of low- and sub-[[parts per billion|ppb]] levels of PFOA in water, food, wildlife, and humans.<ref>{{cite journal |author=Lau C, Butenhoff JL, Rogers JM |title=The developmental toxicity of perfluoroalkyl acids and their derivatives |journal=Toxicol Appl Pharmacol. |volume=198 |issue=2 |pages=231–41 |year=2004 |month=Jul |pmid=15236955 |doi=10.1016/j.taap.2003.11.031 }}</ref>


==Manufacture and uses==
==Manufacture and uses==
PFOA has two main synthesis routes, electrochemical fluorination [[octanoic acid]] fluoride and the direct oxidation of perfluorooctyl iodide.<ref name="Prevedouros2006"/> Using publicly available information, total global PFOA production during 1951-2004 was estimated at 7.2 - 11.4 million pounds with production sites located in the United States, Belgium, Italy, Japan, and Germany.<ref name="Prevedouros2006"/>
PFOA has two main synthesis routes, electrochemical fluorination [[octanoic acid]] fluoride and the direct oxidation of perfluorooctyl iodide.<ref name=Prevedouros2006/> Using publicly available information, total global PFOA production during 1951-2004 was estimated at 7.2 - 11.4 million pounds with production sites located in the United States, Belgium, Italy, Japan, and Germany.<ref name=Prevedouros2006/>


PFOA has widespread applications. Historically, the acid form was the dominant perfluorinated [[carboxylic acid]] used as a reactive intermediate in the production of [[fluoroacrylic esters]].<ref>{{cite journal |author=Kudo N, Suzuki-Nakajima E, Mitsumoto A, Kawashima Y |title=Responses of the liver to perfluorinated fatty acids with different carbon chain length in male and female mice:in relation to induction of hepatomegaly, peroxisomal beta-oxidation and microsomal 1-acylglycerophosphocholine acyltransferase |journal=Biol Pharm Bull. |volume=29 |issue=9 |pages=1952–7 |year=2006 |month=Sep |pmid=16946516 |url=http://joi.jlc.jst.go.jp/JST.JSTAGE/bpb/29.1952?from=PubMed}}</ref> Currently, the [[Salt_(chemistry)|salt]] form is used as an [[emulsion|emulsifier]] for the processing of fluoropolymers such as [[polytetrafluoroethylene]] (PTFE, or [[Teflon]]) and [[polyvinylidene fluoride]] ([[PVDF]]).<ref name="Sandy2008"/><ref name="Lau2007">{{cite journal |author=Lau C, Anitole K, Hodes C, Lai D, Pfahles-Hutchens A, Seed J |title=Perfluoroalkyl acids: a review of monitoring and toxicological findings |journal=Toxicol Sci. |volume=99 |issue=2 |pages=366–94 |year=2007 |month=Oct |pmid=17519394 |doi=10.1093/toxsci/kfm128 }}</ref> In PTFE processing, PFOA is in [[aqueous solution]] and forms [[micelle]]s that contain [[tetrafluoroethylene]] and the growing [[polymer]].<ref>G. Siegemund, W. Schwertfeger, A. Feiring, B. Smart, F. Behr, H. Vogel, B. McKusick in “Fluorine Compounds, Organic” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.</ref> PFOA is used in the production of [[fluoroelastomer]]s.<ref name="Sandy2008"/> PFOA is used in the production of stain-resistant carpets and [[Gore-Tex]].<ref name="Renner2003">Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2003/may/science/rr_surfactant.html "Concerns over common perfluorinated surfactant"] Environmental Science & Technology Online, (May 1, 2003). Accessed September 16, 2008.</ref> Carpet manufacturers of brands such as STAINMASTER have stated that PFOA production and emission from plants are the result of PFOA being an "unwanted byproduct."<ref>Georgia Public Radio: [http://www.gpb.org/georgiagazette/conasauga/chemical "The Chemical in the Conasauga-1: The Chemical in the Conasauga"] Georgia Gazette. (Accessed September 28th, 2008).</ref> However, USEPA scientist John Washington wrote in an email that "...the industry has claimed that PFOA is an unintended impurity, I now suspect that it has been intended---or at least very [c]onvenient---because it helps to stabilize the...particles."<ref>Georgia Public Radio: [http://www.gpb.org/georgiagazette/conasauga/mixed "The Chemical in the Conasauga-10: Mixed Messages"] Georgia Gazette. (Accessed September 28th, 2008).</ref>
PFOA has widespread applications. Historically, the acid form was the dominant perfluorinated [[carboxylic acid]] used as a reactive intermediate in the production of [[fluoroacrylic esters]].<ref>{{cite journal |author=Kudo N, Suzuki-Nakajima E, Mitsumoto A, Kawashima Y |title=Responses of the liver to perfluorinated fatty acids with different carbon chain length in male and female mice:in relation to induction of hepatomegaly, peroxisomal beta-oxidation and microsomal 1-acylglycerophosphocholine acyltransferase |journal=Biol Pharm Bull. |volume=29 |issue=9 |pages=1952–7 |year=2006 |month=Sep |pmid=16946516 |url=http://joi.jlc.jst.go.jp/JST.JSTAGE/bpb/29.1952?from=PubMed}}</ref> Currently, the [[Salt_(chemistry)|salt]] form is used as an [[emulsion|emulsifier]] for the processing of fluoropolymers such as [[polytetrafluoroethylene]] (PTFE, or [[Teflon]]) and [[polyvinylidene fluoride]] ([[PVDF]]).<ref name=Sandy2008/><ref name=Lau2007>{{cite journal |author=Lau C, Anitole K, Hodes C, Lai D, Pfahles-Hutchens A, Seed J |title=Perfluoroalkyl acids: a review of monitoring and toxicological findings |journal=Toxicol Sci. |volume=99 |issue=2 |pages=366–94 |year=2007 |month=Oct |pmid=17519394 |doi=10.1093/toxsci/kfm128 }}</ref> In PTFE processing, PFOA is in [[aqueous solution]] and forms [[micelle]]s that contain [[tetrafluoroethylene]] and the growing [[polymer]].<ref>G. Siegemund, W. Schwertfeger, A. Feiring, B. Smart, F. Behr, H. Vogel, B. McKusick in “Fluorine Compounds, Organic” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.</ref> PFOA is used in the production of [[fluoroelastomer]]s.<ref name=Sandy2008/> PFOA is used in the production of stain-resistant carpets and [[Gore-Tex]].<ref name=Renner2003>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2003/may/science/rr_surfactant.html "Concerns over common perfluorinated surfactant"] Environmental Science & Technology Online, (May 1, 2003). Accessed September 16, 2008.</ref> Carpet manufacturers of brands such as STAINMASTER have stated that PFOA production and emission from plants are the result of PFOA being an "unwanted byproduct."<ref>Georgia Public Radio: [http://www.gpb.org/georgiagazette/conasauga/chemical "The Chemical in the Conasauga-1: The Chemical in the Conasauga"] Georgia Gazette. (Accessed September 28th, 2008).</ref> However, USEPA scientist John Washington wrote in an email that "...the industry has claimed that PFOA is an unintended impurity, I now suspect that it has been intended---or at least very [c]onvenient---because it helps to stabilize the...particles."<ref>Georgia Public Radio: [http://www.gpb.org/georgiagazette/conasauga/mixed "The Chemical in the Conasauga-10: Mixed Messages"] Georgia Gazette. (Accessed September 28th, 2008).</ref>


PFOA is used in aircraft production processes, electronic products, personal care products, and as a perfluorinated industrial surfactant.<ref name="Renner2003"/><ref name="Sandy2008">Martha Sandy: [http://www.oehha.ca.gov/Prop65/public_meetings/pdf/PFOACIC%20Slides121206.pdf "Petition for Expedited CIC Consideration of Perfluorooctanic Acid (PFOA)"] The State of California, Office of Environmental Health Hazard Assessment, Cancer Toxicology and Epidemiology Section, Reproductive and Cancer Hazard Assessment Branch. Accessed September 27, 2008.</ref><ref name="Salager2002">Jean-Louis Salager: [http://nanoparticles.org/pdf/Salager-E300A.pdf "FIRP Booklet # 300-A: Surfactants-Types and Uses"] Universidad de los Andes Laboratory of Formulation, Interfaces Rheology, and Processes. 2002. (Retrieved September 7, 2008).</ref> PFOA is also used in the automotive, chemical, medical, and building/construction industries.<ref name="Sandy2008"/>
PFOA is used in aircraft production processes, electronic products, personal care products, and as a perfluorinated industrial surfactant.<ref name=Renner2003/><ref name=Sandy2008>Martha Sandy: [http://www.oehha.ca.gov/Prop65/public_meetings/pdf/PFOACIC%20Slides121206.pdf "Petition for Expedited CIC Consideration of Perfluorooctanic Acid (PFOA)"] The State of California, Office of Environmental Health Hazard Assessment, Cancer Toxicology and Epidemiology Section, Reproductive and Cancer Hazard Assessment Branch. Accessed September 27, 2008.</ref><ref name=Salager2002>Jean-Louis Salager: [http://nanoparticles.org/pdf/Salager-E300A.pdf "FIRP Booklet # 300-A: Surfactants-Types and Uses"] Universidad de los Andes Laboratory of Formulation, Interfaces Rheology, and Processes. 2002. (Retrieved September 7, 2008).</ref> PFOA is also used in the automotive, chemical, medical, and building/construction industries.<ref name=Sandy2008/>


==Properties==
==Properties==
The [[carboxylate]] "head" of PFOA is [[hydrophilic]] while the perfluorinated tail is [[hydrophobic]] and [[lipophobic]] at the same time, as with other [[perfluorocarbon]]s, because the tail is [[non-polar]] and does not strongly interact through [[van der Waals force]]s.<ref name="Lemal2004">{{cite journal |author=Lemal DM |title=Perspective on fluorocarbon chemistry |journal=J Org Chem. |volume=69 |issue=1 |pages=1–11 |year=2004 |month=Jan |pmid=14703372 |doi=10.1021/jo0302556 }}</ref> PFOA is an ideal surfactant because it can lower the [[surface tension]] of water more than [[hydrocarbon]] surfactants, it has exceptional stability due to the naturally rare carbon-[[fluorine]] (C-F) bonds that are the strongest in organic chemistry, and the C-F bonds also strengthen the underlying backbone carbon-carbon bonds.<ref name="Lemal2004"/><ref name="Lau2007"/><ref name="Salager2002"/> The stability of PFOA is desired industrially, but a cause of concern environmentally. PFOA is resistant to degradation by natural processes such as [[metabolism]], [[hydrolysis]], [[photolysis]], or [[biodegradation]].<ref name="Kudo2003">{{cite journal |author=Kudo N, Kawashima Y |title=Toxicity and toxicokinetics of perfluorooctanoic acid in humans and animals |journal=J Toxicol Sci |volume=28 |issue=2 |pages=49–57 |year=2003 |month=May |pmid=12820537 |url=http://joi.jlc.jst.go.jp/JST.JSTAGE/jts/28.49?from=PubMed}}</ref>
The [[carboxylate]] "head" of PFOA is [[hydrophilic]] while the perfluorinated tail is [[hydrophobic]] and [[lipophobic]] at the same time, as with other [[perfluorocarbon]]s, because the tail is [[non-polar]] and does not strongly interact through [[van der Waals force]]s.<ref name=Lemal2004>{{cite journal |author=Lemal DM |title=Perspective on fluorocarbon chemistry |journal=J Org Chem. |volume=69 |issue=1 |pages=1–11 |year=2004 |month=Jan |pmid=14703372 |doi=10.1021/jo0302556 }}</ref> PFOA is an ideal surfactant because it can lower the [[surface tension]] of water more than [[hydrocarbon]] surfactants, it has exceptional stability due to the naturally rare carbon-[[fluorine]] (C-F) bonds that are the strongest in organic chemistry, and the C-F bonds also strengthen the underlying backbone carbon-carbon bonds.<ref name=Lemal2004/><ref name=Lau2007/><ref name=Salager2002/> The stability of PFOA is desired industrially, but a cause of concern environmentally. PFOA is resistant to degradation by natural processes such as [[metabolism]], [[hydrolysis]], [[photolysis]], or [[biodegradation]].<ref name=Kudo2003>{{cite journal |author=Kudo N, Kawashima Y |title=Toxicity and toxicokinetics of perfluorooctanoic acid in humans and animals |journal=J Toxicol Sci |volume=28 |issue=2 |pages=49–57 |year=2003 |month=May |pmid=12820537 |url=http://joi.jlc.jst.go.jp/JST.JSTAGE/jts/28.49?from=PubMed}}</ref>


PFOA is found in environmental and biological fluids as the anion perfluorooctanoate.<ref name="Emmett2006">{{cite journal |author=Emmett EA, Shofer FS, Zhang H, Freeman D, Desai C, Shaw LM |title=Community exposure to perfluorooctanoate: relationships between serum concentrations and exposure sources |journal=J Occup Environ Med. |volume=48 |issue=8 |pages=759–70 |year=2006 |month=Aug |pmid=16902368 |doi=10.1097/01.jom.0000232486.07658.74 }}</ref> PFOA is absorbed from ingestion and can penetrate [[skin]].<ref name="Kennedy2004"/> The oxygens on PFOA are how it binds [[proteins]] with [[fatty acid]] or [[hormone]] [[substrates]] such as [[albumin|serum albumin]], [[liver]] [[fatty acid]]-binding protein, β-[[lipoprotein]]s, and the [[nuclear receptor]] [[peroxisome proliferator-activated receptor|PPARα]].<ref name="Lau2007"/> PFOA is involved in [[enterohepatic circulation]]. PFOA is mainly present in the [[liver]], blood serum, and [[kidney]] of humans and other animals. PFOA does not accumulate in [[adipose|fat tissue]], unlike most [[organohalogen]] [[persistent organic pollutants]]. In humans, PFOA has an elimination [[half-life]] of about 4 years.<ref name="Renner2003"/> Because of this long half-life, PFOA has the to potential to [[bioaccumulate]].
PFOA is found in environmental and biological fluids as the anion perfluorooctanoate.<ref name=Emmett2006>{{cite journal |author=Emmett EA, Shofer FS, Zhang H, Freeman D, Desai C, Shaw LM |title=Community exposure to perfluorooctanoate: relationships between serum concentrations and exposure sources |journal=J Occup Environ Med. |volume=48 |issue=8 |pages=759–70 |year=2006 |month=Aug |pmid=16902368 |doi=10.1097/01.jom.0000232486.07658.74 }}</ref> PFOA is absorbed from ingestion and can penetrate [[skin]].<ref name=Kennedy2004/> The oxygens on PFOA are how it binds [[proteins]] with [[fatty acid]] or [[hormone]] [[substrates]] such as [[albumin|serum albumin]], [[liver]] [[fatty acid]]-binding protein, β-[[lipoprotein]]s, and the [[nuclear receptor]] [[peroxisome proliferator-activated receptor|PPARα]].<ref name=Lau2007/> PFOA is involved in [[enterohepatic circulation]]. PFOA is mainly present in the [[liver]], blood serum, and [[kidney]] of humans and other animals. PFOA does not accumulate in [[adipose|fat tissue]], unlike most [[organohalogen]] [[persistent organic pollutants]]. In humans, PFOA has an elimination [[half-life]] of about 4 years.<ref name=Renner2003/> Because of this long half-life, PFOA has the to potential to [[bioaccumulate]].


==Global occurence==
==Global occurence==
PFOA is found on every [[continent]].<ref name="Betts2007">Kellyn S. Betts [http://www.ehponline.org/members/2007/115-5/focus.html "Perfluoroalkyl Acids: What Is the Evidence Telling Us?"] ''Environmental Health Perspectives'' Volume 115, Number 5, May 2007. Accessed October, 18 2008.</ref> PFOA has been detected in the central Pacific Ocean and at higher levels in [[coastal waters]].<ref>Yamashita N, Kannan K, Taniyasu S, Horii Y, Petrick G, Gamo T.: [http://www.ncbi.nlm.nih.gov/pubmed/15913661 "A Global Survey of Perfluorinated Acids in Oceans"], Mar Poll Bull. 2005;51(8-12):658-68.</ref> Due to the surfactant nature of PFOA, it has been found to concentrate in the top layers of ocean water and may even concentrate further into [[sea spray]] [[aerosols]].<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/apr/science/rr_pfoatransport.html "Aerosols complicate PFOA picture"] Environmental Science & Technology Online. (April 28, 2008). Accessed October 4, 2008.</ref> PFOA is detected widely in [[surface water]]s, and is present in numerous mammal, fish, and bird species including [[polar bear]]s and giant pandas.<ref name="Betts2007"/> PFOA has also been detected in the blood of humans globally. In the United States, concentrations of PFOA in blood serum have declined by 25% in recent years.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/may/science/rr_pfosblood.html "PFOS phaseout pays off"] ''Environmental Science & Technology Online''. (May 21, 2008). Accessed October 19, 2008.</ref>
PFOA is found on every [[continent]].<ref name=Betts2007>{{cite journal |author=Betts KS |title=Perfluoroalkyl acids: what is the evidence telling us? |journal=Environ. Health Perspect. |volume=115 |issue=5 |pages=A250–6 |year=2007 |month=May |pmid=17520044 |url=http://www.ehponline.org/members/2007/115-5/focus.html}}</ref> PFOA has been detected in the central Pacific Ocean and at higher levels in [[coastal waters]].<ref>{{cite journal |author=Yamashita N, Kannan K, Taniyasu S, Horii Y, Petrick G, Gamo T |title=A global survey of perfluorinated acids in oceans |journal=Mar Pollut Bull. |volume=51 |issue=8-12 |pages=658–68 |year=2005 |pmid=15913661 |doi=10.1016/j.marpolbul.2005.04.026 }}</ref> Due to the surfactant nature of PFOA, it has been found to concentrate in the top layers of ocean water and may even concentrate further into [[sea spray]] [[aerosols]].<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/apr/science/rr_pfoatransport.html "Aerosols complicate PFOA picture"] Environmental Science & Technology Online. (April 28, 2008). Accessed October 4, 2008.</ref> PFOA is detected widely in [[surface water]]s, and is present in numerous mammal, fish, and bird species including [[polar bear]]s and giant pandas.<ref name=Betts2007/> PFOA has also been detected in the blood of humans globally. In the United States, concentrations of PFOA in blood serum have declined by 25% in recent years.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/may/science/rr_pfosblood.html "PFOS phaseout pays off"] ''Environmental Science & Technology Online''. (May 21, 2008). Accessed October 19, 2008.</ref>


==Sources==
==Sources==
===Industrial sites===
===Industrial sites===
PFOA is released directly from industrial sites. For example, the DuPont Washington Works facility in [[Washington, WV]] estimated total PFOA emissions of 80,000 [[Pound (mass)|lbs]] in [[2000]] and 1,700 lbs in [[2004]].<ref name="Emmett2006"/> A [[2006]] study, with two of four authors DuPont empolyees, estimated about 80% of historical perfluorocarboxylate emissions were released to the environment from [[fluoropolymer]] manufacture and use.<ref name="Prevedouros2006"/> PFOA can be measured in water from industrial sites other than flurochemical plants. PFOA has also been detected in emissions from the [[Dalton,_Georgia#Carpet_industry|carpet industry]]<ref name="Fuchs2008">Fuchs, Erin and Pam Sohn: [http://www.timesfreepress.com/news/2008/feb/10/epa-finds-high-levels-stain-resistance-ingredient "Study finds high levels of stain-resistance ingredient in Conasauga River"] Chattanooga Times Free Press. (February 10, 2008). Accessed October 4, 2008.</ref> and paper industry.<ref>Clara M, Scheffknecht C, Scharf S, Weiss S, Gans O.: [http://www.ncbi.nlm.nih.gov/pubmed/18653937 "Emissions of perfluorinated alkylated substances (PFAS) from point sources--identification of relevant branches"] Water Sci Technol. 2008;58(1):59-66.</ref>
PFOA is released directly from industrial sites. For example, the DuPont Washington Works facility in [[Washington, WV]] estimated total PFOA emissions of 80,000 [[Pound (mass)|lbs]] in [[2000]] and 1,700 lbs in [[2004]].<ref name=Emmett2006/> A [[2006]] study, with two of four authors DuPont empolyees, estimated about 80% of historical perfluorocarboxylate emissions were released to the environment from [[fluoropolymer]] manufacture and use.<ref name=Prevedouros2006/> PFOA can be measured in water from industrial sites other than flurochemical plants. PFOA has also been detected in emissions from the [[Dalton,_Georgia#Carpet_industry|carpet industry]]<ref name=Fuchs2008>Fuchs, Erin and Pam Sohn: [http://www.timesfreepress.com/news/2008/feb/10/epa-finds-high-levels-stain-resistance-ingredient "Study finds high levels of stain-resistance ingredient in Conasauga River"] Chattanooga Times Free Press. (February 10, 2008). Accessed October 4, 2008.</ref> and paper industry.<ref>{{cite journal |author=Clara M, Scheffknecht C, Scharf S, Weiss S, Gans O |title=Emissions of perfluorinated alkylated substances (PFAS) from point sources—identification of relevant branches |journal=Water Sci Technol. |volume=58 |issue=1 |pages=59–66 |year=2008 |pmid=18653937 |doi=10.2166/wst.2008.641 }}</ref>


===PFOA precursors===
===PFOA precursors===
PFOA can form as a breakdown product from a variety of precursor molecules. PFOA precursors can be transformed to PFOA by metabolism, biodegradation, or atmospheric processes. Examples include 8:2 [[fluorotelomer alcohol]] (H(CF<sub>2</sub>)<sub>8</sub>CH<sub>2</sub>CH<sub>2</sub>OH),<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2006/jan/science/rr_leftovers.html "Manufacturing leftovers may help explain the puzzling presence of perfluorinated compounds"] ''Environmental Science and Technology Online''.(January 25, 2006). Accessed October 19, 2008.</ref> [[polyfloroalkyl phosphate surfactants]] (PAPS),<ref name="Renner2007">Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2007/may/science/rr_PFOApeople.html "PFOA in People"] Environmental Science & Technology Online, (May 23, 2007).</ref> and [[PFOS#PFOS_Precursors|N-EtFOSE alcohol]] (F(CF<sub>2</sub>)<sub>8</sub>SO<sub>2</sub>N(Et)CH<sub>2</sub>CH<sub>2</sub>OH).<ref>Cleston C. Lange: [http://www.nikwax.com/cmsdata/Downloads/pr/5-3M_biodegradation_report.pdf "The Aerobic Biodegradation of N-EtFOSE Alcohol by the Microbial Activity Present in Municipal Wastewater Treatment Sludge"] Pace Analytical Services, Science Solutions Division, (November 1, 2000). Accessed September 19, 2008.</ref> The [[OECD]] has compiled a list of chemicals that have the potential to break down into perfluorocarboxylic acids (PFCA) including PFOA.<ref>Organisation for Economic Co-operation and Development: [http://www.olis.oecd.org/olis/2006doc.nsf/LinkTo/NT00000F9A/$FILE/JT03231059.PDF "Lists of PFOS, PFAS, PFOA, PFCA, related compounds and chemicals that may degrade to PFCA"] Environment Directorate-Joint Meeting of the Chemicals Committee and the Working Party on Chemicals, Pesticides, and Biotechnology, (August 21, 2007). Accessed September 19, 2008.</ref> The [[OECD]] identified 615 chemicals that potentially break down to form PFCA. However, not all of these chemicals have the potential to break down to form PFOA.
PFOA can form as a breakdown product from a variety of precursor molecules. PFOA precursors can be transformed to PFOA by metabolism, biodegradation, or atmospheric processes. Examples include 8:2 [[fluorotelomer alcohol]] (H(CF<sub>2</sub>)<sub>8</sub>CH<sub>2</sub>CH<sub>2</sub>OH),<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2006/jan/science/rr_leftovers.html "Manufacturing leftovers may help explain the puzzling presence of perfluorinated compounds"] ''Environmental Science and Technology Online''.(January 25, 2006). Accessed October 19, 2008.</ref> [[polyfloroalkyl phosphate surfactants]] (PAPS),<ref name=Renner2007>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2007/may/science/rr_PFOApeople.html "PFOA in People"] Environmental Science & Technology Online, (May 23, 2007).</ref> and [[PFOS#PFOS_Precursors|N-EtFOSE alcohol]] (F(CF<sub>2</sub>)<sub>8</sub>SO<sub>2</sub>N(Et)CH<sub>2</sub>CH<sub>2</sub>OH).<ref>Cleston C. Lange: [http://www.nikwax.com/cmsdata/Downloads/pr/5-3M_biodegradation_report.pdf "The Aerobic Biodegradation of N-EtFOSE Alcohol by the Microbial Activity Present in Municipal Wastewater Treatment Sludge"] Pace Analytical Services, Science Solutions Division, (November 1, 2000). Accessed September 19, 2008.</ref> The [[OECD]] has compiled a list of chemicals that have the potential to break down into perfluorocarboxylic acids (PFCA) including PFOA.<ref>Organisation for Economic Co-operation and Development: [http://www.olis.oecd.org/olis/2006doc.nsf/LinkTo/NT00000F9A/$FILE/JT03231059.PDF "Lists of PFOS, PFAS, PFOA, PFCA, related compounds and chemicals that may degrade to PFCA"] Environment Directorate-Joint Meeting of the Chemicals Committee and the Working Party on Chemicals, Pesticides, and Biotechnology, (August 21, 2007). Accessed September 19, 2008.</ref> The [[OECD]] identified 615 chemicals that potentially break down to form PFCA. However, not all of these chemicals have the potential to break down to form PFOA.


A majority of [[waste water treatment plants]] (WWTPs) that have been tested ouput more PFOA than is input, and this increased output has been attributed to the biodegradation of fluorotelomer alcohols.<ref>Melissa M. Schultz, Christopher P. Higgins, Carin A. Huset, Richard G. Luthy, Douglas F. Barofsky, and Jennifer A. Field: [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2556954 "Fluorochemical Mass Flows in a Municipal Wastewater Treatment Facility"] ''Environ Sci Technol''. 2006 December 1; 40(23): 7350–7357.</ref> A current PFOA precursor concern are the stability of fluoropolymers themselves; fluorotelomer alcohols attached to products via [[ester]] linkages and fluoroacrylic esters may biodegrade to PFOA.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/jan/science/rr_fluorotelomer.html "Do perfluoropolymers biodegrade into PFOA?"] ''Environmental Science & Technology Online''. (January 8, 2008). Accessed October 25, 2008.</ref>
A majority of [[waste water treatment plants]] (WWTPs) that have been tested ouput more PFOA than is input, and this increased output has been attributed to the biodegradation of fluorotelomer alcohols.<ref>{{cite journal |author=Schultz MM, Higgins CP, Huset CA, Luthy RG, Barofsky DF, Field JA |title=Fluorochemical mass flows in a municipal wastewater treatment facility |journal=Environ Sci Technol. |volume=40 |issue=23 |pages=7350–7 |year=2006 |month=Dec |pmid=17180988 |pmc=2556954}}</ref> A current PFOA precursor concern are the stability of fluoropolymers themselves; fluorotelomer alcohols attached to products via [[ester]] linkages and fluoroacrylic esters may biodegrade to PFOA.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2008/jan/science/rr_fluorotelomer.html "Do perfluoropolymers biodegrade into PFOA?"] ''Environmental Science & Technology Online''. (January 8, 2008). Accessed October 25, 2008.</ref>


===Sources to People===
===Sources to People===
[[Food]], [[drinking water]], outdoor [[air]], indoor air, [[dust]], and [[food packaging]]s are all implicated as sources of PFOA to people.<ref name="Renner2007"/> Contaminated food and drinking water are thought to be the largest contributors, while consumer products such as impregnation sprays ([[textile]] treatments), treated carpets, and coated food contact materials are considered as minor.<ref>Trudel D, Horowitz L, Wormuth M, Scheringer M, Cousins IT, Hungerbühler K.: [http://www.ncbi.nlm.nih.gov/pubmed/18419647 "Estimating consumer exposure to PFOS and PFOA"] Risk Anal. 2008 Apr;28(2):251-69.</ref> Citizens that lived in the PFOA contaminated area around DuPont's Washington Works Washington, WV facility were found to have higher levels of PFOA in their blood from drinking water. The highest PFOA levels in drinking water were found in the Little Hocking water system, with an average concentration of 3.55 [[parts per billion|ppb]] during 2002-2005.<ref name="Emmett2006"/> Individuals who drank more tap water, ate locally grown fruits and vegetables, or ate local meat, were all associated with having higher PFOA levels. Residents who used water [[Carbon filtering|carbon filter]] systems had lower PFOA levels.
[[Food]], [[drinking water]], outdoor [[air]], indoor air, [[dust]], and [[food packaging]]s are all implicated as sources of PFOA to people.<ref name=Renner2007/> Contaminated food and drinking water are thought to be the largest contributors, while consumer products such as impregnation sprays ([[textile]] treatments), treated carpets, and coated food contact materials are considered as minor.<ref>{{cite journal |author=Trudel D, Horowitz L, Wormuth M, Scheringer M, Cousins IT, Hungerbühler K |title=Estimating consumer exposure to PFOS and PFOA |journal=Risk Anal. |volume=28 |issue=2 |pages=251–69 |year=2008 |month=Apr |pmid=18419647 |doi=10.1111/j.1539-6924.2008.01017.x }}</ref> Citizens that lived in the PFOA contaminated area around DuPont's Washington Works Washington, WV facility were found to have higher levels of PFOA in their blood from drinking water. The highest PFOA levels in drinking water were found in the Little Hocking water system, with an average concentration of 3.55 [[parts per billion|ppb]] during 2002-2005.<ref name=Emmett2006/> Individuals who drank more tap water, ate locally grown fruits and vegetables, or ate local meat, were all associated with having higher PFOA levels. Residents who used water [[Carbon filtering|carbon filter]] systems had lower PFOA levels.


===Fluorotelomer and Teflon food contact surfaces===
===Fluorotelomer and Teflon food contact surfaces===
PFOA is also formed as an unintended byproduct in the production of [[fluorotelomers]]<ref>DuPont, [http://www2.dupont.com/PFOA/en_US/ "Information on PFOA"] Accessed Sep 2 2006.</ref> and is present in finished goods, including those intended for food contact. In an [[U.S. Food and Drug Administration]] (FDA) study, fluorotelomer-based paper coatings (which can be applied to food contact paper in the concentration range of 0.4%) were found to contain 88,000-160,000 ppb PFOA, while [[Popcorn bag|microwave popcorn bags]] contained 6-290 ppb PFOA, and residual PFOA was also detected in finished [[PTFE]] products including PTFE/[[Teflon]] cookware.<ref name="Begley2005">Begley TH, White K, Honigfort P, Twaroski ML, Neches R, Walker RA.: [http://www.ncbi.nlm.nih.gov/pubmed/16227186 "Perfluorochemicals: potential sources of and migration from food packaging"] Food Addit Contam. 2005 Oct;22(10):1023-31.</ref> In a New York State Department of Health study, PFOA was detected in the gas phase coming from new nonstick cookware and microwave popcorn bags;<ref>Sinclair E, Kim SK, Akinleye HB, Kannan K.: [http://www.ncbi.nlm.nih.gov/pubmed/17593716 "Quantitation of gas-phase perfluoroalkyl surfactants and fluorotelomer alcohols released from nonstick cookware and microwave popcorn bags"] Environ Sci Technol. 2007 Feb 15;41(4):1180-5.</ref> this research was funded by a 2005-2006 $17,700 grant from the [[Consumers Union]].<ref>ISI Web of Knowledge [http://hcr3.isiknowledge.com/author.cgi?id=5765&cb=579 "ISI Highly Cited Researchers - A0213-2006-J"] Thomson ISI. Last updated September 26, 2006, (Accessed September 7, 2008).</ref> Toxicologists estimate that microwave popcorn could account for about 20% of the PFOA levels measured in an individual consuming 10 bags a year if 1% of the fluorotelomers are metabolized to PFOA.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2005/nov/science/rr_popcorn.html "It’s in the microwave popcorn, not the Teflon pan"] Environmental Science and Technology Online (November 16, 2005).</ref> Fluorotelomer-based paper coatings are used in direct food contact because of their [[lipophobicity]]; the coatings give papers resistance to oil soaking in from fatty foods.<ref name="Begley2005"/> Fluorotelomer coatings are used in fast food wrappers, candy wrappers, and pizza box liners.<ref>Elizabeth Weise: [http://www.usatoday.com/money/companies/management/2005-11-16-dupont-usat_x.htm "Engineer: DuPont hid facts about paper coating"] USA Today, (November 16, 2005). Accessed September 19, 2008.</ref> PAPS, a type of paper fluorotelomer coating, and PFOA precursor, is also used in food contact papers.<ref name="Renner2007"/>
PFOA is also formed as an unintended byproduct in the production of [[fluorotelomers]]<ref>DuPont, [http://www2.dupont.com/PFOA/en_US/ "Information on PFOA"] Accessed Sep 2 2006.</ref> and is present in finished goods, including those intended for food contact. In an [[U.S. Food and Drug Administration]] (FDA) study, fluorotelomer-based paper coatings (which can be applied to food contact paper in the concentration range of 0.4%) were found to contain 88,000-160,000 ppb PFOA, while [[Popcorn bag|microwave popcorn bags]] contained 6-290 ppb PFOA, and residual PFOA was also detected in finished [[PTFE]] products including PTFE/[[Teflon]] cookware.<ref name=Begley2005>{{cite journal |author=Begley TH, White K, Honigfort P, Twaroski ML, Neches R, Walker RA |title=Perfluorochemicals: potential sources of and migration from food packaging |journal=Food Addit Contam |volume=22 |issue=10 |pages=1023–31 |year=2005 |month=Oct |pmid=16227186 |doi=10.1080/02652030500183474 }}</ref> In a New York State Department of Health study, PFOA was detected in the gas phase coming from new nonstick cookware and microwave popcorn bags;<ref>{{cite journal |author=Sinclair E, Kim SK, Akinleye HB, Kannan K |title=Quantitation of gas-phase perfluoroalkyl surfactants and fluorotelomer alcohols released from nonstick cookware and microwave popcorn bags |journal=Environ Sci Technol. |volume=41 |issue=4 |pages=1180–5 |year=2007 |month=Feb |pmid=17593716 }}</ref> this research was funded by a 2005-2006 $17,700 grant from the [[Consumers Union]].<ref>ISI Web of Knowledge [http://hcr3.isiknowledge.com/author.cgi?id=5765&cb=579 "ISI Highly Cited Researchers - A0213-2006-J"] Thomson ISI. Last updated September 26, 2006, (Accessed September 7, 2008).</ref> Toxicologists estimate that microwave popcorn could account for about 20% of the PFOA levels measured in an individual consuming 10 bags a year if 1% of the fluorotelomers are metabolized to PFOA.<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2005/nov/science/rr_popcorn.html "It’s in the microwave popcorn, not the Teflon pan"] Environmental Science and Technology Online (November 16, 2005).</ref> Fluorotelomer-based paper coatings are used in direct food contact because of their [[lipophobicity]]; the coatings give papers resistance to oil soaking in from fatty foods.<ref name=Begley2005/> Fluorotelomer coatings are used in fast food wrappers, candy wrappers, and pizza box liners.<ref>Elizabeth Weise: [http://www.usatoday.com/money/companies/management/2005-11-16-dupont-usat_x.htm "Engineer: DuPont hid facts about paper coating"] USA Today, (November 16, 2005). Accessed September 19, 2008.</ref> PAPS, a type of paper fluorotelomer coating, and PFOA precursor, is also used in food contact papers.<ref name=Renner2007/>


===Other products===
===Other products===
Residual PFOA is found in aqueous film forming foam (AFFF), a component of [[fire-fighting foam]]s. Residual PFOA has also been detected in stain-resistant carpet (200-2000 [[parts per billion|ppb]]), mill-treated carpeting (200-600 ppb), treated apparel (up to 1400 ppb, and treated home textiles (up to 1400 ppb).<ref name="Washburn2005">Washburn ST, Bingman TS, Braithwaite SK, Buck RC, Buxton LW, Clewell HJ, Haroun LA, Kester JE, Rickard RW, Shipp AM.: [http://www.ncbi.nlm.nih.gov/pubmed/15984763 "Exposure assessment and risk characterization for perfluorooctanoate in selected consumer articles"] Environ Sci Technol. 2005 Jun 1;39(11):3904-10.</ref> PFOA was detected in the low-ppb range in industrial floor waxes and wax removers, latex paint, and home and office cleaners.<ref name="Washburn2005"/> Upon extraction PFOA was also detected in treated upholstery.<ref name="Washburn2005"/>
Residual PFOA is found in aqueous film forming foam (AFFF), a component of [[fire-fighting foam]]s. Residual PFOA has also been detected in stain-resistant carpet (200-2000 [[parts per billion|ppb]]), mill-treated carpeting (200-600 ppb), treated apparel (up to 1400 ppb, and treated home textiles (up to 1400 ppb).<ref name=Washburn2005>{{cite journal |author=Washburn ST, Bingman TS, Braithwaite SK, ''et al'' |title=Exposure assessment and risk characterization for perfluorooctanoate in selected consumer articles |journal=Environ Sci Technol. |volume=39 |issue=11 |pages=3904–10 |year=2005 |month=Jun |pmid=15984763 }}</ref> PFOA was detected in the low-ppb range in industrial floor waxes and wax removers, latex paint, and home and office cleaners.<ref name=Washburn2005/> Upon extraction PFOA was also detected in treated upholstery.<ref name=Washburn2005/>


==Health concerns==
==Health concerns==
===Animal data===
===Animal data===
PFOA is a liver toxicant, a developmental toxicant, an immune system toxicant, and also exerts [[hormonal]] effects.<ref name="Lau2007"/> PFOA alters [[lipid metabolism]].<ref name="Betts2007"/> Animal studies show developmental toxicity from reduced birth size, physical developmental delays, [[endocrine disruption]], and [[Perinatal mortality|neonatal mortality]].<ref name="Betts2007"/><ref name="Betts2007b">Kellyn Betts: [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2072861 "PFOS and PFOA in Humans: New Study Links Prenatal Exposure to Lower Birth Weight"] ''Environmental Health Perspectives'' 2007 November; 115(11): A550.</ref> PFOA alters [[thyroid hormone]] levels.<ref name="Lau2007"/> PFOA is a liver [[carcinogen]] in rodents. PFOA is an [[agonist]] of [[peroxisome proliferator-activated receptor|PPARα]] and is a [[peroxisome]] proliferator in rodents,<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2001/dec/science/rr_foam.html "Foam spill study suggests perfluorinated surfactants’ fate"] ''Environmental Science & Technology Online'' (December, 2001). Accessed October 18, 2008.</ref> contributing to a well understood form of [[oxidative stress]].<ref name="Hood2008">Ernie Hood: [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2516576 "Alternative Mechanism for PFOA?: Trout Studies Shed Light on Liver Effects"] ''Environ Health Perspect''. 2008 August; 116(8): A351.</ref> However, humans are considered less susceptible to peroxisome proliferation than rodents, and recently PFOA was found to be a liver carcinogen in [[rainbow trout]] via an [[estrogenic]] mechanism, which may be more relevant to humans.<ref name="Hood2008"/>
PFOA is a liver toxicant, a developmental toxicant, an immune system toxicant, and also exerts [[hormonal]] effects.<ref name=Lau2007/> PFOA alters [[lipid metabolism]].<ref name=Betts2007/> Animal studies show developmental toxicity from reduced birth size, physical developmental delays, [[endocrine disruption]], and [[Perinatal mortality|neonatal mortality]].<ref name=Betts2007/><ref name=Betts2007b>{{cite journal |author=Betts K |title=PFOS and PFOA in humans: new study links prenatal exposure to lower birth weight |journal=Environ Health Perspect. |volume=115 |issue=11 |pages=A550 |year=2007 |month=Nov |pmid=18007977 |pmc=2072861 }}</ref> PFOA alters [[thyroid hormone]] levels.<ref name=Lau2007/> PFOA is a liver [[carcinogen]] in rodents. PFOA is an [[agonist]] of [[peroxisome proliferator-activated receptor|PPARα]] and is a [[peroxisome]] proliferator in rodents,<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2001/dec/science/rr_foam.html "Foam spill study suggests perfluorinated surfactants’ fate"] ''Environmental Science & Technology Online'' (December, 2001). Accessed October 18, 2008.</ref> contributing to a well understood form of [[oxidative stress]].<ref name=Hood2008>Ernie Hood: [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2516576 "Alternative Mechanism for PFOA?: Trout Studies Shed Light on Liver Effects"] ''Environ Health Perspect''. 2008 August; 116(8): A351.</ref> However, humans are considered less susceptible to peroxisome proliferation than rodents, and recently PFOA was found to be a liver carcinogen in [[rainbow trout]] via an [[estrogenic]] mechanism, which may be more relevant to humans.<ref name=Hood2008/>


A [[2007]] USEPA toxicology review states, regarding PFOA and [[PFOS]], that "neither compound has been shown to be [[mutagenic]] in a variety of assays" and then cites three sources: one authored by 3M, one authored by 3M, DuPont, [[Covance]], Atofina, and Ineos Chlor, and one from the USEPA.<ref name="Lau2007"/> As early as [[1991]] researchers from Japan demonstrated [[oxidative stress|oxidative]] liver [[DNA]] damage in an experiment with rats.<ref>Takagi A, Sai K, Umemura T, Hasegawa R, Kurokawa Y.: [http://www.ncbi.nlm.nih.gov/pubmed/2025879 "Short-term exposure to the peroxisome proliferators, perfluorooctanoic acid and perfluorodecanoic acid, causes significant increase of 8-hydroxydeoxyguanosine in liver DNA of rats"] Cancer Lett. 1991 Apr;57(1):55-60.</ref> In Germany criteria have been proposed that would allow PFOA, and other perfluorinated compounds, to be classified as "weakly non-specific [[genotoxic]]."<ref name="Roos2008">Roos PH, Angerer J, Dieter H, Wilhelm M, Wölfle D, Hengstler JG: [http://www.ncbi.nlm.nih.gov/pubmed/17687546 "Perfluorinated compounds (PFC) hit the headlines: meeting report on a satellite symposium of the annual meeting of the German Society of Toxicology"] Arch Toxicol. 2008 Jan;82(1):57-9. Epub 2007 Aug 9.</ref>
A [[2007]] USEPA toxicology review states, regarding PFOA and [[PFOS]], that "neither compound has been shown to be [[mutagenic]] in a variety of assays" and then cites three sources: one authored by 3M, one authored by 3M, DuPont, [[Covance]], Atofina, and Ineos Chlor, and one from the USEPA.<ref name=Lau2007/> As early as [[1991]] researchers from Japan demonstrated [[oxidative stress|oxidative]] liver [[DNA]] damage in an experiment with rats.<ref>{{cite journal |author=Takagi A, Sai K, Umemura T, Hasegawa R, Kurokawa Y |title=Short-term exposure to the peroxisome proliferators, perfluorooctanoic acid and perfluorodecanoic acid, causes significant increase of 8-hydroxydeoxyguanosine in liver DNA of rats |journal=Cancer Lett. |volume=57 |issue=1 |pages=55–60 |year=1991 |month=Apr |pmid=2025879 |url=http://linkinghub.elsevier.com/retrieve/pii/0304-3835(91)90063-N}}</ref> In Germany criteria have been proposed that would allow PFOA, and other perfluorinated compounds, to be classified as "weakly non-specific [[genotoxic]]."<ref name=Roos2008>{{cite journal |author=Roos PH, Angerer J, Dieter H, Wilhelm M, Wölfle D, Hengstler JG |title=Perfluorinated compounds (PFC) hit the headlines : meeting report on a satellite symposium of the annual meeting of the German Society of Toxicology |journal=Arch Toxicol. |volume=82 |issue=1 |pages=57–9 |year=2008 |month=Jan |pmid=17687546 |doi=10.1007/s00204-007-0225-2 }}</ref>


===Human data===
===Human data===
The levels of PFOA exposure in humans varies widely. While an average American might have 3 or 4 [[parts per billion|ppb]] of PFOA present in their blood serum, individuals occupationally exposed to PFOA have had blood serum levels over 100,000 ppb (100 [[parts per million|ppm]]) recorded.<ref>3M [http://solutions.3m.com/wps/portal/3M/en_US/PFOS/PFOA/Information/Health-Environment/ "PFOS-PFOA: Human Health and the Environment"] Accessed October 18, 2008.</ref> In a study of individuals living around DuPont's Washington Works WV plant, those who had no occupational exposure had a [[median]] blood serum level of 329 ppb while the median of those with occupational exposure was 775 ppb.<ref name="Emmett2006"/>
The levels of PFOA exposure in humans varies widely. While an average American might have 3 or 4 [[parts per billion|ppb]] of PFOA present in their blood serum, individuals occupationally exposed to PFOA have had blood serum levels over 100,000 ppb (100 [[parts per million|ppm]]) recorded.<ref>3M [http://solutions.3m.com/wps/portal/3M/en_US/PFOS/PFOA/Information/Health-Environment/ "PFOS-PFOA: Human Health and the Environment"] Accessed October 18, 2008.</ref> In a study of individuals living around DuPont's Washington Works WV plant, those who had no occupational exposure had a [[median]] blood serum level of 329 ppb while the median of those with occupational exposure was 775 ppb.<ref name=Emmett2006/>


For the general population, blood serum levels of PFOA have been linked to lower birth weight in babies.<ref>Crystal Phend, Reviewed by Zalman S. Agus [http://www.medpagetoday.com/PublicHealthPolicy/EnvironmentalHealth/6515 "Nonstick Chemical Linked to Lower Birth Weight"] ''MedPage Today'' (August 27, 2007). Accessed November 1, 2008.</ref><ref name="Betts2007b"/> In response to media coverage from these two studies, the [[American Council on Science and Health]] labeled the idea that "''PFOA Causes Low Birth Weight Babies''" as #4 on their Top Ten Unfounded Health Scares of 2007, arguing that "PFOA affecting birth weight by four [[ounce]]s does not imply any real harm to the babies - they were all of normal weight."<ref>American Council on Science and Health: [http://wwz.acsh.org/publications/pubID.1653/pub_detail.asp "Top Ten Unfounded Health Scares of 2007 #4: PFOA Causes Low Birth Weight Babies"] (December 19, 2007). Accessed October 18, 2008.</ref> More recently, a smaller Canadian study did not find any inverse relationship between PFOA levels and birth weight.<ref>Monroy R, Morrison K, Teo K, Atkinson S, Kubwabo C, Stewart B, Foster WG.: [http://www.ncbi.nlm.nih.gov/pubmed/18649879 "Serum levels of perfluoroalkyl compounds in human maternal and umbilical cord blood samples"] Environ Res. 2008 Sep;108(1):56-62. Epub 2008 Jul 22.</ref>
For the general population, blood serum levels of PFOA have been linked to lower birth weight in babies.<ref>Crystal Phend, Reviewed by Zalman S. Agus [http://www.medpagetoday.com/PublicHealthPolicy/EnvironmentalHealth/6515 "Nonstick Chemical Linked to Lower Birth Weight"] ''MedPage Today'' (August 27, 2007). Accessed November 1, 2008.</ref><ref name=Betts2007b/> In response to media coverage from these two studies, the [[American Council on Science and Health]] labeled the idea that "''PFOA Causes Low Birth Weight Babies''" as #4 on their Top Ten Unfounded Health Scares of 2007, arguing that "PFOA affecting birth weight by four [[ounce]]s does not imply any real harm to the babies - they were all of normal weight."<ref>American Council on Science and Health: [http://wwz.acsh.org/publications/pubID.1653/pub_detail.asp "Top Ten Unfounded Health Scares of 2007 #4: PFOA Causes Low Birth Weight Babies"] (December 19, 2007). Accessed October 18, 2008.</ref> More recently, a smaller Canadian study did not find any inverse relationship between PFOA levels and birth weight.<ref>{{cite journal |author=Monroy R, Morrison K, Teo K, ''et al'' |title=Serum levels of perfluoroalkyl compounds in human maternal and umbilical cord blood samples |journal=Environ Res. |volume=108 |issue=1 |pages=56–62 |year=2008 |month=Sep |pmid=18649879 |doi=10.1016/j.envres.2008.06.001 }}</ref>


For more highly exposed populations, a [[2000]] 3M [[epidemiology]] study recorded [[statistically significant]] increases in [[cholesterol]], [[triglyceride]], and [[triiodothyronine]] levels and a statistically significant decrease in [[High-density lipoprotein|HDL]] with increasing levels of PFOA.<ref name="Kudo2003"/> A 3M funded study found workers who were highly exposed to PFOA had twice the odds of dying from [[prostate cancer]] and [[stroke]] when compared to other workers at the same plant; in response, 3M's spokesman said, "nothing in this study changes our conclusion that there are no adverse health effects from PFOA."<ref>Tom Meersman: [http://www.startribune.com/local/east/16321036.html "Study: Death rate up for 3M workers exposed to PFOA"] ''Star Tribune'' (March 5, 2008). Accessed October 18, 2008.</ref> A DuPont report on the rate of occurrence of [[carcinoid]] tumors at their Washington, WV plant gave "preliminary evidence for a [[cancer cluster]]."<ref name="Eder2008">Andrew Eder: [http://www.defendingscience.org/upload/DuPont-Plant-Linked-to-Cancer-News-Journal-June-10-2008.pdf "DuPont plant linked to cancer"] ''The News Journal''. (June 12, 2008). Accessed October 19, 2008.</ref> DuPont responded by stating that they did not have any reason to believe the increase from the Washington Works plant was due to any specific chemical.<ref name="Eder2008"/> In a [[May]] [[2008]] preliminary report released by [[West Virginia University]] (WVU), PFOA was linked to liver, thyroid, immune system, and cholesterol changes considered harmful in the population around DuPont's Washington, WV plant.<ref name="ENS2008">[http://www.ens-newswire.com/ens/may2008/2008-05-13-093.asp "Chemical Used to Make Non-Stick Coatings Harmful to Health"] ''Environment News Service'' (May 13, 2008). Accessed October 19, 2008.</ref> In a quick response to the release of the WVU report, DuPont's spokesman highlighted the preliminary nature and the legal issue of the C8 Science Panel being the only court appointed authority on study results.<ref name="Brust2008">Pamela Brust: [http://www.newsandsentinel.com/page/content.detail/id/505434.html?nav=5061 "Swift react to C8 study"] ''Parkersberg News and Sentinel''. (May 17, 2008.) Accessed October 19, 2008.</ref> The C8 Science Panel also criticized the WVU release, labeling the graphs as "simple" that related PFOA to several blood tests because they did not represent a "thorough data analysis."<ref name="Brust2008"/> In [[October]] [[2008]], when the C8 Science Panel released findings, PFOA was only linked to high levels of cholesterol.<ref name="Finn2008">Scott Finn: [http://www.wvpubcast.org/newsarticle.aspx?id=5466 "C8 study shows link with high cholesterol"] ''West Virginia Public Broadcasting'' (October 16, 2008). Accessed October 18, 2008.</ref> Despite evidence PFOA has ''biological effects'' in humans (that are likely harmful to human health), DuPont's position is that the data does not ''prove'' PFOA causes ''health'' effects.<ref name="Finn2008"/>
For more highly exposed populations, a [[2000]] 3M [[epidemiology]] study recorded [[statistically significant]] increases in [[cholesterol]], [[triglyceride]], and [[triiodothyronine]] levels and a statistically significant decrease in [[High-density lipoprotein|HDL]] with increasing levels of PFOA.<ref name=Kudo2003/> A 3M funded study found workers who were highly exposed to PFOA had twice the odds of dying from [[prostate cancer]] and [[stroke]] when compared to other workers at the same plant; in response, 3M's spokesman said, "nothing in this study changes our conclusion that there are no adverse health effects from PFOA."<ref>Tom Meersman: [http://www.startribune.com/local/east/16321036.html "Study: Death rate up for 3M workers exposed to PFOA"] ''Star Tribune'' (March 5, 2008). Accessed October 18, 2008.</ref> A DuPont report on the rate of occurrence of [[carcinoid]] tumors at their Washington, WV plant gave "preliminary evidence for a [[cancer cluster]]."<ref name=Eder2008>Andrew Eder: [http://www.defendingscience.org/upload/DuPont-Plant-Linked-to-Cancer-News-Journal-June-10-2008.pdf "DuPont plant linked to cancer"] ''The News Journal''. (June 12, 2008). Accessed October 19, 2008.</ref> DuPont responded by stating that they did not have any reason to believe the increase from the Washington Works plant was due to any specific chemical.<ref name=Eder2008/> In a [[May]] [[2008]] preliminary report released by [[West Virginia University]] (WVU), PFOA was linked to liver, thyroid, immune system, and cholesterol changes considered harmful in the population around DuPont's Washington, WV plant.<ref name=ENS2008>[http://www.ens-newswire.com/ens/may2008/2008-05-13-093.asp "Chemical Used to Make Non-Stick Coatings Harmful to Health"] ''Environment News Service'' (May 13, 2008). Accessed October 19, 2008.</ref> In a quick response to the release of the WVU report, DuPont's spokesman highlighted the preliminary nature and the legal issue of the C8 Science Panel being the only court appointed authority on study results.<ref name=Brust2008>Pamela Brust: [http://www.newsandsentinel.com/page/content.detail/id/505434.html?nav=5061 "Swift react to C8 study"] ''Parkersberg News and Sentinel''. (May 17, 2008.) Accessed October 19, 2008.</ref> The C8 Science Panel also criticized the WVU release, labeling the graphs as "simple" that related PFOA to several blood tests because they did not represent a "thorough data analysis."<ref name="Brust2008"/> In [[October]] [[2008]], when the C8 Science Panel released findings, PFOA was only linked to high levels of cholesterol.<ref name="Finn2008">Scott Finn: [http://www.wvpubcast.org/newsarticle.aspx?id=5466 "C8 study shows link with high cholesterol"] ''West Virginia Public Broadcasting'' (October 16, 2008). Accessed October 18, 2008.</ref> Despite evidence PFOA has ''biological effects'' in humans (that are likely harmful to human health), DuPont's position is that the data does not ''prove'' PFOA causes ''health'' effects.<ref name="Finn2008"/>


A [[2008]] legal opinion stated that health concerns from PFOA exposed citizens around DuPont's Washington Works WV plant were justified. Chief Judge Joseph R. Goodwin wrote that the "plaintiffs have presented compelling evidence that exposure to C-8 may be harmful to human health, and the evidence certainly justifies the concerns expressed by the plaintiffs in this case."<ref name="Goodwin2008">Goodwin, C.J. [http://www.wvsd.uscourts.gov/district/opinions/pdf/RhodesvDuPontMemOp.pdf "''Rhodes, et al. v. E.I. Du Pont De Nemours and Company''"] [[United States District Court for the Southern District of West Virginia]]. Case Number, 6:06-cv-530 (September 30, 2008). Accessed October 12, 2008.</ref>
A [[2008]] legal opinion stated that health concerns from PFOA exposed citizens around DuPont's Washington Works WV plant were justified. Chief Judge Joseph R. Goodwin wrote that the "plaintiffs have presented compelling evidence that exposure to C-8 may be harmful to human health, and the evidence certainly justifies the concerns expressed by the plaintiffs in this case."<ref name=Goodwin2008>Goodwin, C.J. [http://www.wvsd.uscourts.gov/district/opinions/pdf/RhodesvDuPontMemOp.pdf "''Rhodes, et al. v. E.I. Du Pont De Nemours and Company''"] [[United States District Court for the Southern District of West Virginia]]. Case Number, 6:06-cv-530 (September 30, 2008). Accessed October 12, 2008.</ref>


==Regulatory Status==
==Regulatory Status==
There is no federal standard for PFOA in drinking water in the United States.<ref name="Betts2007"/> There is no federal safety standard for PFOA in consumer products in the United States.<ref name="ENS2008"/>
There is no federal standard for PFOA in drinking water in the United States.<ref name=Betts2007/> There is no federal safety standard for PFOA in consumer products in the United States.<ref name=ENS2008/>


==Actions==
==Actions==
Line 102: Line 102:
On [[December 13]], [[2005]], DuPont announced a settlement with the EPA in which DuPont will pay [[United States dollar|US$]]10.25 million in fines and an additional US$6.25 million for two supplemental environmental projects without any admission of liability.
On [[December 13]], [[2005]], DuPont announced a settlement with the EPA in which DuPont will pay [[United States dollar|US$]]10.25 million in fines and an additional US$6.25 million for two supplemental environmental projects without any admission of liability.


On [[September 30]], [[2008]], Chief Judge Joseph R. Goodwin of the [[United States District Court for the Southern District of West Virginia]] denied the certification of a class because residents exposed to PFOA from DuPont's Washington Works WV facility did not "show the common individual injuries needed to certify a class action."<ref name="Goodwin2008"/>
On [[September 30]], [[2008]], Chief Judge Joseph R. Goodwin of the [[United States District Court for the Southern District of West Virginia]] denied the certification of a class because residents exposed to PFOA from DuPont's Washington Works WV facility did not "show the common individual injuries needed to certify a class action."<ref name=Goodwin2008/>


===U.S. Federal Government Actions===
===U.S. Federal Government Actions===
In [[2002]], a panel of toxicologists, including several from the [[USEPA]], proposed a level of 150 [[parts per billion|ppb]] for [[drinking water]] in the PFOA contaminated area around DuPont's Washington Works WV plant; this level was much higher than any known environmental concentration.<ref name="Renner2003"/>
In [[2002]], a panel of toxicologists, including several from the [[USEPA]], proposed a level of 150 [[parts per billion|ppb]] for [[drinking water]] in the PFOA contaminated area around DuPont's Washington Works WV plant; this level was much higher than any known environmental concentration.<ref name=Renner2003/>


In [[July]] [[2004]], the [[USEPA]] filed a suit against [[DuPont]] alleging "widespread contamination" of PFOA near the Parkersburg, WV plant "at levels exceeding the company’s community exposure guidelines;" the suit also alleged that "DuPont had - over a 20 year period - repeatedly failed to submit information on adverse effects (in particular, information on liver enzyme alterations and birth defects in offspring of female Parkersburg workers)."<ref name="Clapp"/>
In [[July]] [[2004]], the [[USEPA]] filed a suit against [[DuPont]] alleging "widespread contamination" of PFOA near the Parkersburg, WV plant "at levels exceeding the company’s community exposure guidelines;" the suit also alleged that "DuPont had - over a 20 year period - repeatedly failed to submit information on adverse effects (in particular, information on liver enzyme alterations and birth defects in offspring of female Parkersburg workers)."<ref name="Clapp"/>


In [[October]] [[2005]], a [[U.S. Food and Drug Administration]] study was published revealing PFOA and PFOA precursor chemicals in food contact and [[PTFE]]/[[Teflon]] products.<ref name="Begley2005"/>
In [[October]] [[2005]], a [[U.S. Food and Drug Administration]] study was published revealing PFOA and PFOA precursor chemicals in food contact and [[PTFE]]/[[Teflon]] products.<ref name=Begley2005/>


On [[January 25]], [[2006]], the [[USEPA]] announced a voluntary program with several chemical companies to reduce PFOA and PFOA precursor emissions by the year 2015.<ref>USEPA: [http://www.epa.gov/opptintr/pfoa/pubs/pfoastewardship.htm "2010/15 PFOA Stewardship Program"] Accessed September 19, 2008.</ref> Since then, it has become obvious that other companies and industries operate outside of the voluntary program.<ref name="Fuchs2008"/>
On [[January 25]], [[2006]], the [[USEPA]] announced a voluntary program with several chemical companies to reduce PFOA and PFOA precursor emissions by the year 2015.<ref>USEPA: [http://www.epa.gov/opptintr/pfoa/pubs/pfoastewardship.htm "2010/15 PFOA Stewardship Program"] Accessed September 19, 2008.</ref> Since then, it has become obvious that other companies and industries operate outside of the voluntary program.<ref name=Fuchs2008/>


On [[February 15]], [[2005]], the [[USEPA]]'s Science Advisory Board (SAB) voted to recommended that PFOA should be considered a "likely human [[carcinogen]]."<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2006/mar/policy/rr_PFOAreduction.html "Scientists hail PFOA reduction plan"] ''Environmental Science & Technology Online''. Policy News. (March 15, 2005). Accessed October 26, 2008.</ref>
On [[February 15]], [[2005]], the [[USEPA]]'s Science Advisory Board (SAB) voted to recommended that PFOA should be considered a "likely human [[carcinogen]]."<ref>Renner, Rebecca: [http://pubs.acs.org/subscribe/journals/esthag-w/2006/mar/policy/rr_PFOAreduction.html "Scientists hail PFOA reduction plan"] ''Environmental Science & Technology Online''. Policy News. (March 15, 2005). Accessed October 26, 2008.</ref>

Revision as of 09:50, 13 November 2008

Perfluorooctanoic acid
Names
IUPAC name
pentadecafluorooctanoic acid
Other names
perfluorooctanoic acid, PFOA Perfluorocaprylic acid, FC-143, F-n-octanoic acid
Identifiers
3D model (JSmol)
ECHA InfoCard 100.005.817 Edit this at Wikidata
RTECS number
  • RH0781000
  • OC(=O)C(F)(F)C(F)(F)C(F)(F)C
    (F)(F)C(F)(F)C(F)(F)C(F)(F)F
Properties
C8HF15O2
Molar mass 414.07 g/mol
Appearance colorless liquid
Density 1.8 g/cm3 [1]
Melting point 40–50 °C [1]
Boiling point 189–192 °C [1]
soluble, 3.4 g/L (PFO)[1]
Solubility in other solvents polar organic
solvents
Acidity (pKa) 0
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Strong Acid, Causes Burns
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Perfluorooctanoic acid (PFOA), also known as C8, is a man-made acid that has many industrial uses. PFOA can designate the acid itself, the principal salts (like ammonium perfluorooctanoate, also known as APFO), or the dissociated conjugate base perfluorooctanoate (also known as PFO). PFOA is a potent surfactant and a persistent ubiquitous global contaminant. It is detected in the blood serum of general populations and its biological effects are under investigation. PFOA is also produced from the degradation of a variety of precursors.

History

In 1947, 3M began producing PFOA by the electrochemical fluorination method.[2] In 1951, DuPont started using PFOA in the manufacturing of fluoropolymers in Washington, WV.[3] In 1961, DuPont was aware of hepatomegaly in mice fed PFOA.[4][5] In 1968, organofluorine content was detected in the blood serum of consumers, and in 1976 it was suggested to likely be PFOA.[6] In 1980, PFOA was identified as the primary organofluorine present in the blood serum of fluorochemical production workers.[7] In the 1980s and 1990s researchers investigated the toxicity of PFOA. In 1999, the USEPA began investigating perfluorinated chemicals after receiving data on the global distribution and toxicity of PFOS.[8] For these reasons, in May of 2000, 3M announced the phaseout of the production of PFOA, PFOS, and PFOS-related products.[9] After the PFOA-phaseout by 3M, increased attention has been directed towards PFOA, DuPont, and the USEPA, as described below. Additionally, advances in analytical chemistry in recent years have allowed the routine detection of low- and sub-ppb levels of PFOA in water, food, wildlife, and humans.[10]

Manufacture and uses

PFOA has two main synthesis routes, electrochemical fluorination octanoic acid fluoride and the direct oxidation of perfluorooctyl iodide.[2] Using publicly available information, total global PFOA production during 1951-2004 was estimated at 7.2 - 11.4 million pounds with production sites located in the United States, Belgium, Italy, Japan, and Germany.[2]

PFOA has widespread applications. Historically, the acid form was the dominant perfluorinated carboxylic acid used as a reactive intermediate in the production of fluoroacrylic esters.[11] Currently, the salt form is used as an emulsifier for the processing of fluoropolymers such as polytetrafluoroethylene (PTFE, or Teflon) and polyvinylidene fluoride (PVDF).[12][13] In PTFE processing, PFOA is in aqueous solution and forms micelles that contain tetrafluoroethylene and the growing polymer.[14] PFOA is used in the production of fluoroelastomers.[12] PFOA is used in the production of stain-resistant carpets and Gore-Tex.[15] Carpet manufacturers of brands such as STAINMASTER have stated that PFOA production and emission from plants are the result of PFOA being an "unwanted byproduct."[16] However, USEPA scientist John Washington wrote in an email that "...the industry has claimed that PFOA is an unintended impurity, I now suspect that it has been intended---or at least very [c]onvenient---because it helps to stabilize the...particles."[17]

PFOA is used in aircraft production processes, electronic products, personal care products, and as a perfluorinated industrial surfactant.[15][12][18] PFOA is also used in the automotive, chemical, medical, and building/construction industries.[12]

Properties

The carboxylate "head" of PFOA is hydrophilic while the perfluorinated tail is hydrophobic and lipophobic at the same time, as with other perfluorocarbons, because the tail is non-polar and does not strongly interact through van der Waals forces.[19] PFOA is an ideal surfactant because it can lower the surface tension of water more than hydrocarbon surfactants, it has exceptional stability due to the naturally rare carbon-fluorine (C-F) bonds that are the strongest in organic chemistry, and the C-F bonds also strengthen the underlying backbone carbon-carbon bonds.[19][13][18] The stability of PFOA is desired industrially, but a cause of concern environmentally. PFOA is resistant to degradation by natural processes such as metabolism, hydrolysis, photolysis, or biodegradation.[20]

PFOA is found in environmental and biological fluids as the anion perfluorooctanoate.[3] PFOA is absorbed from ingestion and can penetrate skin.[6] The oxygens on PFOA are how it binds proteins with fatty acid or hormone substrates such as serum albumin, liver fatty acid-binding protein, β-lipoproteins, and the nuclear receptor PPARα.[13] PFOA is involved in enterohepatic circulation. PFOA is mainly present in the liver, blood serum, and kidney of humans and other animals. PFOA does not accumulate in fat tissue, unlike most organohalogen persistent organic pollutants. In humans, PFOA has an elimination half-life of about 4 years.[15] Because of this long half-life, PFOA has the to potential to bioaccumulate.

Global occurence

PFOA is found on every continent.[21] PFOA has been detected in the central Pacific Ocean and at higher levels in coastal waters.[22] Due to the surfactant nature of PFOA, it has been found to concentrate in the top layers of ocean water and may even concentrate further into sea spray aerosols.[23] PFOA is detected widely in surface waters, and is present in numerous mammal, fish, and bird species including polar bears and giant pandas.[21] PFOA has also been detected in the blood of humans globally. In the United States, concentrations of PFOA in blood serum have declined by 25% in recent years.[24]

Sources

Industrial sites

PFOA is released directly from industrial sites. For example, the DuPont Washington Works facility in Washington, WV estimated total PFOA emissions of 80,000 lbs in 2000 and 1,700 lbs in 2004.[3] A 2006 study, with two of four authors DuPont empolyees, estimated about 80% of historical perfluorocarboxylate emissions were released to the environment from fluoropolymer manufacture and use.[2] PFOA can be measured in water from industrial sites other than flurochemical plants. PFOA has also been detected in emissions from the carpet industry[25] and paper industry.[26]

PFOA precursors

PFOA can form as a breakdown product from a variety of precursor molecules. PFOA precursors can be transformed to PFOA by metabolism, biodegradation, or atmospheric processes. Examples include 8:2 fluorotelomer alcohol (H(CF2)8CH2CH2OH),[27] polyfloroalkyl phosphate surfactants (PAPS),[28] and N-EtFOSE alcohol (F(CF2)8SO2N(Et)CH2CH2OH).[29] The OECD has compiled a list of chemicals that have the potential to break down into perfluorocarboxylic acids (PFCA) including PFOA.[30] The OECD identified 615 chemicals that potentially break down to form PFCA. However, not all of these chemicals have the potential to break down to form PFOA.

A majority of waste water treatment plants (WWTPs) that have been tested ouput more PFOA than is input, and this increased output has been attributed to the biodegradation of fluorotelomer alcohols.[31] A current PFOA precursor concern are the stability of fluoropolymers themselves; fluorotelomer alcohols attached to products via ester linkages and fluoroacrylic esters may biodegrade to PFOA.[32]

Sources to People

Food, drinking water, outdoor air, indoor air, dust, and food packagings are all implicated as sources of PFOA to people.[28] Contaminated food and drinking water are thought to be the largest contributors, while consumer products such as impregnation sprays (textile treatments), treated carpets, and coated food contact materials are considered as minor.[33] Citizens that lived in the PFOA contaminated area around DuPont's Washington Works Washington, WV facility were found to have higher levels of PFOA in their blood from drinking water. The highest PFOA levels in drinking water were found in the Little Hocking water system, with an average concentration of 3.55 ppb during 2002-2005.[3] Individuals who drank more tap water, ate locally grown fruits and vegetables, or ate local meat, were all associated with having higher PFOA levels. Residents who used water carbon filter systems had lower PFOA levels.

Fluorotelomer and Teflon food contact surfaces

PFOA is also formed as an unintended byproduct in the production of fluorotelomers[34] and is present in finished goods, including those intended for food contact. In an U.S. Food and Drug Administration (FDA) study, fluorotelomer-based paper coatings (which can be applied to food contact paper in the concentration range of 0.4%) were found to contain 88,000-160,000 ppb PFOA, while microwave popcorn bags contained 6-290 ppb PFOA, and residual PFOA was also detected in finished PTFE products including PTFE/Teflon cookware.[35] In a New York State Department of Health study, PFOA was detected in the gas phase coming from new nonstick cookware and microwave popcorn bags;[36] this research was funded by a 2005-2006 $17,700 grant from the Consumers Union.[37] Toxicologists estimate that microwave popcorn could account for about 20% of the PFOA levels measured in an individual consuming 10 bags a year if 1% of the fluorotelomers are metabolized to PFOA.[38] Fluorotelomer-based paper coatings are used in direct food contact because of their lipophobicity; the coatings give papers resistance to oil soaking in from fatty foods.[35] Fluorotelomer coatings are used in fast food wrappers, candy wrappers, and pizza box liners.[39] PAPS, a type of paper fluorotelomer coating, and PFOA precursor, is also used in food contact papers.[28]

Other products

Residual PFOA is found in aqueous film forming foam (AFFF), a component of fire-fighting foams. Residual PFOA has also been detected in stain-resistant carpet (200-2000 ppb), mill-treated carpeting (200-600 ppb), treated apparel (up to 1400 ppb, and treated home textiles (up to 1400 ppb).[40] PFOA was detected in the low-ppb range in industrial floor waxes and wax removers, latex paint, and home and office cleaners.[40] Upon extraction PFOA was also detected in treated upholstery.[40]

Health concerns

Animal data

PFOA is a liver toxicant, a developmental toxicant, an immune system toxicant, and also exerts hormonal effects.[13] PFOA alters lipid metabolism.[21] Animal studies show developmental toxicity from reduced birth size, physical developmental delays, endocrine disruption, and neonatal mortality.[21][41] PFOA alters thyroid hormone levels.[13] PFOA is a liver carcinogen in rodents. PFOA is an agonist of PPARα and is a peroxisome proliferator in rodents,[42] contributing to a well understood form of oxidative stress.[43] However, humans are considered less susceptible to peroxisome proliferation than rodents, and recently PFOA was found to be a liver carcinogen in rainbow trout via an estrogenic mechanism, which may be more relevant to humans.[43]

A 2007 USEPA toxicology review states, regarding PFOA and PFOS, that "neither compound has been shown to be mutagenic in a variety of assays" and then cites three sources: one authored by 3M, one authored by 3M, DuPont, Covance, Atofina, and Ineos Chlor, and one from the USEPA.[13] As early as 1991 researchers from Japan demonstrated oxidative liver DNA damage in an experiment with rats.[44] In Germany criteria have been proposed that would allow PFOA, and other perfluorinated compounds, to be classified as "weakly non-specific genotoxic."[45]

Human data

The levels of PFOA exposure in humans varies widely. While an average American might have 3 or 4 ppb of PFOA present in their blood serum, individuals occupationally exposed to PFOA have had blood serum levels over 100,000 ppb (100 ppm) recorded.[46] In a study of individuals living around DuPont's Washington Works WV plant, those who had no occupational exposure had a median blood serum level of 329 ppb while the median of those with occupational exposure was 775 ppb.[3]

For the general population, blood serum levels of PFOA have been linked to lower birth weight in babies.[47][41] In response to media coverage from these two studies, the American Council on Science and Health labeled the idea that "PFOA Causes Low Birth Weight Babies" as #4 on their Top Ten Unfounded Health Scares of 2007, arguing that "PFOA affecting birth weight by four ounces does not imply any real harm to the babies - they were all of normal weight."[48] More recently, a smaller Canadian study did not find any inverse relationship between PFOA levels and birth weight.[49]

For more highly exposed populations, a 2000 3M epidemiology study recorded statistically significant increases in cholesterol, triglyceride, and triiodothyronine levels and a statistically significant decrease in HDL with increasing levels of PFOA.[20] A 3M funded study found workers who were highly exposed to PFOA had twice the odds of dying from prostate cancer and stroke when compared to other workers at the same plant; in response, 3M's spokesman said, "nothing in this study changes our conclusion that there are no adverse health effects from PFOA."[50] A DuPont report on the rate of occurrence of carcinoid tumors at their Washington, WV plant gave "preliminary evidence for a cancer cluster."[51] DuPont responded by stating that they did not have any reason to believe the increase from the Washington Works plant was due to any specific chemical.[51] In a May 2008 preliminary report released by West Virginia University (WVU), PFOA was linked to liver, thyroid, immune system, and cholesterol changes considered harmful in the population around DuPont's Washington, WV plant.[52] In a quick response to the release of the WVU report, DuPont's spokesman highlighted the preliminary nature and the legal issue of the C8 Science Panel being the only court appointed authority on study results.[53] The C8 Science Panel also criticized the WVU release, labeling the graphs as "simple" that related PFOA to several blood tests because they did not represent a "thorough data analysis."[53] In October 2008, when the C8 Science Panel released findings, PFOA was only linked to high levels of cholesterol.[54] Despite evidence PFOA has biological effects in humans (that are likely harmful to human health), DuPont's position is that the data does not prove PFOA causes health effects.[54]

A 2008 legal opinion stated that health concerns from PFOA exposed citizens around DuPont's Washington Works WV plant were justified. Chief Judge Joseph R. Goodwin wrote that the "plaintiffs have presented compelling evidence that exposure to C-8 may be harmful to human health, and the evidence certainly justifies the concerns expressed by the plaintiffs in this case."[55]

Regulatory Status

There is no federal standard for PFOA in drinking water in the United States.[21] There is no federal safety standard for PFOA in consumer products in the United States.[52]

Actions

Industry and Legal Actions

DuPont has used PFOA for over 50 years at its Washington Works plant near Parkersburg, WV. Area residents sued DuPont in 2001, claiming that the chemical contaminated area drinking water (DuPont and C-8). As part of the settlement, DuPont is paying for blood tests and health surveys of residents believed to be affected. Up to 60,000 people are expected to participate in the study, which will be reviewed by epidemiologists to determine any long-term health effects.

In 2002 Burger King stopped using fluorotelomer coated boxes.[56]

On December 13, 2005, DuPont announced a settlement with the EPA in which DuPont will pay US$10.25 million in fines and an additional US$6.25 million for two supplemental environmental projects without any admission of liability.

On September 30, 2008, Chief Judge Joseph R. Goodwin of the United States District Court for the Southern District of West Virginia denied the certification of a class because residents exposed to PFOA from DuPont's Washington Works WV facility did not "show the common individual injuries needed to certify a class action."[55]

U.S. Federal Government Actions

In 2002, a panel of toxicologists, including several from the USEPA, proposed a level of 150 ppb for drinking water in the PFOA contaminated area around DuPont's Washington Works WV plant; this level was much higher than any known environmental concentration.[15]

In July 2004, the USEPA filed a suit against DuPont alleging "widespread contamination" of PFOA near the Parkersburg, WV plant "at levels exceeding the company’s community exposure guidelines;" the suit also alleged that "DuPont had - over a 20 year period - repeatedly failed to submit information on adverse effects (in particular, information on liver enzyme alterations and birth defects in offspring of female Parkersburg workers)."[5]

In October 2005, a U.S. Food and Drug Administration study was published revealing PFOA and PFOA precursor chemicals in food contact and PTFE/Teflon products.[35]

On January 25, 2006, the USEPA announced a voluntary program with several chemical companies to reduce PFOA and PFOA precursor emissions by the year 2015.[57] Since then, it has become obvious that other companies and industries operate outside of the voluntary program.[25]

On February 15, 2005, the USEPA's Science Advisory Board (SAB) voted to recommended that PFOA should be considered a "likely human carcinogen."[58]

On May 26, 2006, the USEPA's SAB addressed a letter to Stephen L. Johnson. Three-quarters of advisers thought the stronger "likely to be carcinogenic" descriptor was warranted, in opposition to the USEPA's own PFOA hazard descriptor of "suggestive evidence of carcinogenicity, but not sufficient to assess human carcinogenic potential."[59]

On November 21, 2006, the USEPA ordered DuPont company to offer alternative drinking water or treatment for public or private water users living near DuPont's Washington Works plant in West Virginia (and in Ohio), if the level of PFOA detected in drinking water is equal to or greater than 0.5 ppb. This measure sharply lowered the previous action level of 150 ppb that was established in March 2002.[60]

According to a May 23, 2007, Environmental Science & Technology Online article, U.S. Food and Drug Administration research regarding food contact papers as a potential source of PFOA to humans is ongoing.[28]

In November 2007, the Centers for Disease Control and Prevention (CDC) published data on PFOA concentrations comparing 1999-2000 vs. 2003-2004 NHANES samples.[61]

U.S. State Government Actions

On February 13, 2007, the New Jersey Department of Environmental Protection issued a preliminary health-based guidance level of 0.04 ppb in drinking water, due to PFOA being found at "elevated levels in the system's drinking water near DuPont's massive Chambers Works chemical plant."[62]

On March 1, 2007, the Minnesota Department of Health lowered its Health Based Value for PFOA in drinking water from 1.0 ppb to 0.5 ppb,[63] where "the sources are landfilled industrial wastes from a 3M manufacturing plant."[64]

European action

PFOA contaminated waste was incorporated into soil improver and spread on agricultural land in Germany, leading to PFOA drinking water contamination of up to 0.519 ppb.[65][66] The German Federal Environmental Agency issued guidelines for the sum of PFOA and PFOS concentrations in drinking water: 0.1 ppb for precaution and 0.3 ppb for a threshold.[45] Residents were found to have a 6-8 factor increase of PFOA serum levels over unexposed Germans, with average PFOA concentrations in the 22-27 ppb range.[21] An expert panel concluded that "concentrations were considered too low to cause overt adverse health effects in the exposed population."[45]

See also

External links

References

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