United States
       Environmental Protection
               Emerging Contaminants-
  Perfluorooctane Sulfonate (PFOS)
and Perfluorooctanoic Acid  (PFOA)
                                                                            May 2012
                              EMERGING CONTAMINANTS FACT SHEET - PFOS and PFOA
   At a Glance

   *  Fully fluorinated compounds
       that are human-made
       substances and not naturally
       found in the environment.
   *  Used as a surface-active
       agent and in variety of
       products, such as fire fighting
       foams, coating additives and
       cleaning products.
   *  Does not hydrolyze, photolyze
       or biodegrade under
       environmental conditions and
       is extremely persistent in the
   *  Studies have shown  it has the
       potential to bioaccumulate and
       biomagnify in wildlife.
   *  Readily absorbed after oral
       exposure and accumulates
       primarily in the serum, kidney,
       and liver.
   *  Toxicological studies on
       animals indicate potential
       developmental, reproductive
       and systematic effects.
   *  Health-based advisories or
       screening levels for PFOS and
       PFOA have been developed
       by  both the EPA and the
   *  Standard detection methods
       include high-performance
       liquid chromatographyand
       tandem mass spectrometry
   *  Common water treatment
       technologies include activated
       carbon filters and reverse
       osmosis units.
     An "emerging contaminant" is a chemical or material that is characterized by
     a perceived, potential or real threat to human health or the environment or by
     a lack of published health standards. A contaminant may also be "emerging"
     because a new source or a new pathway to humans has been discovered or
     a new detection method or treatment technology has been developed (DoD
     2011). This fact sheet, developed by the U.S. Environmental Protection
     Agency's Federal Facilities Restoration and Reuse Office (FFRRO), provides
     a brief summary of the emerging contaminants perfluorooctane sulfonate
     (PFOS) and perfluorooctanoicacid (PFOA), including physical and chemical
     properties; environmental and health impacts; existing federal and state
     guidelines; detection and treatment methods; and additional sources of

     PFOS and PFOA are extremely persistent in the environment and can be
     transported long distances in air. As a result, they are widely distributed
     across the higher trophic levels and are found in soil, air and groundwater at
     sites across the United States. The toxicity and  bioaccumulation potential of
     PFOS and PFOA indicate a cause of concern for the environment and
     human health. This fact sheet is intended for use by site managers faced
     with addressing PFOS and PFOA at cleanup sites or in drinking water
     supplies and for those in a position to  consider whether these chemicals
     should be added to the analytical suite for site investigations.

     What are PFOS and PFOA?                          	

     >  PFOS and PFOA are fully fluorinated, organic compounds and are the
         largest made perflourinated chemicals (PFCs) (ATSDR2009).

     >  PFOS is a perfluoralkyl sulfonate that is commonly used as a simple salt
         (such as potassium, sodium, or ammonium) or incorporated into larger
         polymers (EFSA2008; EPA2009a).
     >  PFOA is a perfluoralkyl carboxylate that is produced synthetically as its
         salts. Ammonium salt is the most widely produced form  (EFSA 2008;
     >  PFOS synonyms include 1-Octanesulfonicacid, 1-Octanesulfonicacid,
         Heptadecafluoro-, 1-Perfluorooctanesulfonicacid, Heptadecafluoro-1-
         octanesulfonicacid,  Perfluoro-n-octanesulfonicacid,
         Perfluoroctanesulfonicacid, and Perfluoroctylsulfonicacid  (ATSDR2009;
     >  PFOA synonyms include pentadecafluorol -octanoic acid,
         pentadecafluoro-n-octanoicacid; pentadecaflurooctanoicacid;
         perfluorocaprylic perfluoroctanoicacid; perfluoroheptanecarboxylic acid;
         and octanoic acid (ATSDR 2009).
  United States
  Environmental Protection Agency
               Solid Waste and
               Emergency Response (5106P)
EPA 505-F-11-002
       May 2012
  Disclaimer: The U.S. EPA prepared this fact sheet from publicly available sources that were available at the time the fact sheet was published; additional information can be
obtained from the source documents. This fact sheet is not intended to be used as a primary source of information and is not intended, nor can it be relied on, to create any rights
  enforceable by any party in litigation with the United States. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.


  Emerging Contaminants Fact Sheet - PFOS and PFOA
What are PFOS and PFOA? (continued)
   They are stable chemicals made of a long carbon
   chain that is both lipid- and water-repellent.
   Because of the unique amphiphilic character,
   PFOS and PFOA are used as surface-active
   agents in various high-temperature applications
   and for applications in contact with strong acids or
   bases (ATSDR 2009; UNEP 2005).
   They are used in a wide variety of industrial and
   commercial products such as textiles and leather
   products; fire fighting foams, metal plating, the
   photographic industry, photolithography, semi-
   conductors, paper and packaging, coating
   additives, cleaning products, and pesticides
   (OECD 2002; EFSA 2008).
   They are human-made compounds and do not
   naturally occur in the environment (ATSDR 2009;
   UNEP 2006).
   PFOS and PFOA can be formed by environmental
   microbial degradation or by metabolism in larger
   organisms from a large group of related
   substances or precursor compounds (ATSDR
   2009; Condor etal. 2010; UNEP 2006).
           The 3M Company, the primary manufacturer of
           PFOS, completed a voluntary phase-out of PFOS
           production in 2002 (ATSDR 2009; UNEP 2007).
           PFOS chemicals are no longer manufactured in
           United States. However, they can be imported and
           used for specific limited  uses (EPA 2009a).
           PFOA is primarily manufactured for use as an
           aqueous dispersion agent, as ammonium salt, in
           the manufacture of fluoropolymers, which are used
           in a wide variety of mechanical and industrial
           components. They are also produced
           unintentionally by the degradation of some
           fluorotelomers (EPA 2009a).
           As part of the EPA's PFOA stewardship program,
           eight companies committed to reduce global
           facility emission and product content of PFOA and
           related chemicals by 95 percent in 2010 and
           eliminating emission and product content by 2015
           (ATSDR 2009; EPA 2012).
                     Exhibit 1: Physical and Chemical Properties of PFOS and PFOA
          (ATSDR 2009; Brooke et al. 2004; Cheng et al. 2008; EFSA 2008; EPA 2002; UNEP 2006)
CAS Number
Physical Description (physical state at room
temperature and atmospheric pressure)
Molecular weight (g/mol)
Water solubility (mg/L at 25C)
Melting Point (C)
Boiling point (C)
Vapor pressure at 20 C (mm Hg)
Air water partition coefficient (Pa.mJ/mol)
Octanol-water partition coefficient (log Kow)
Organic-carbon partition coefficient (log Koc)
Henry's law constant (atm m3/mol)
PFOS (Potassium Salt)
White Powder
538 (potassium salt)
570 (purified), 370 (freshwater), 25
(filtered seawater)
Not measurable
< 2 X1 0'
Not measurable
3.05 x 10"9
Atmospheric: 114 days
Water: > 41 years (at 25 C)
Photolytic: > 3.7 years
Sonolysis: 20 to 63 minutes
White powder/waxy white
45 to 50
Not available
Not measurable
Not measurable
Atmospheric: 90 days
Water: > 92 years (at 25 C)
Photolytic: > 349 days
Sonolysis: 20 to 63 minutes
Notes: g/mol - grams per mole; mg/L - milligrams per
Pa m3/mol - pascal-cubic meters per mole; atm m3/mol
liter; C - degree Celsius; mm Hg - millimeters of mercury;
- atmosphere-cubic meters per mole.

  Emerging Contaminants Fact Sheet - PFOS and PFOA
What are the environmental impacts of PFOS and PFOA?
    During past manufacturing processes, large
    amounts of PFOS and PFOA were released to the
    air, water and soil in and around fluorochemical
    facilities (ATSDR 2009; UNEP 2006).
    PFOS and PFOA have been detected in a number
    of U.S. cities in surface water and sediments
    downstream of former production facilities,
    wastewater treatment plant effluent, sewage
    sludge, and landfill leachate (EPA 2002; OECD
    PFOS and PFOA are chemically and biologically
    stable in the environment and resistant to
    biodegradation, atmospheric photooxidation, direct
    photolysis, and hydrolysis. As a result, these
    chemicals are extremely persistent in the
    environment (ATSDR 2009; EFSA 2008).
    No transformation of PFOS or PFOA has been
    observed in soil, sediment, sludge, water or biota
    systems. Progressive shortening of PFOS and
    PFOA has been  observed in the atmosphere
    (Conderetal. 2010).
    Low acid dissociation constants (pKa) ranging from
    -3 to 4 suggest that PFOS and  PFOA are strong
    acids  and exist predominately in the anionicform in
    the environment (Conder et al.  2010).
    As a result of the chemical stability of PFOS and
    PFOA and the low volatility of these substances in
    ionic form, these substances are persistent in
    water and soil (ATSDR 2009).
    Additionally, PFOS and PFOA can be transported
    long distances in air because of their high
    atmospheric half-lives (ATSDR 2009; UNEP
Monitoring data, including at sites remote from
known point sources, have shown highly elevated
levels of PFOS and PFOA throughout the northern
hemisphere and indicate that long-range transport
has occurred (ATSDR 2009; UNEP 2005; 2007).
The wide distribution of the chemicals in high
trophic levels increases the potential for
bioaccumulation and bioconcentration. Because of
their persistence and long-term accumulation,
higher trophic level wildlife such as fish,
piscivorous birds, and Arctic biota can continue to
be exposed to PFOS and PFOA (EPA 2006;
UNEP 2006).
PFOS exhibits a higher tendency to bind to
organic matter and bioaccumulate compared to
PFOA due to its longer perfluoroalkyl chain length
(Conderetal. 2010).
PFOS has been shown to bioaccumulate and
biomagnify in wildlife species such as fish and
piscivorous birds. The biomagnification factor
ranges from 1.4 to 17 kilogram per kilogram
(kg/kg) in predatory birds and mammals
(Moermond et al. 2010; UNEP 2006).
PFOS is the only PFC that has been shown to
accumulate to levels of concern in fish tissue. The
estimated kinetic bioconcentration factor in  fish
ranges from 1,000 to 4,000 (EFSA 2008; MDH
PFOS and PFOA have not been reported at the
EPA's National Priorities List (NPL) sites;
however, it is unknown how many of the current or
former NPL sites have been evaluated for the
presence of these chemicals (ATSDR 2009).
What are the health effects of PFOS and PFOA?
   Studies have found small quantities of PFOS and
   PFOA in the blood samples of humans and wildlife
   nationwide, indicating that exposure to the
   chemicals is widespread (3M 2000; EPA 2006).
   Potential pathways, which may lead to widespread
   exposure,  include ingestion of food and water,  use
   of commercial products, or inhalation from long-
   range air transport (ATSDR 2009;  EPA 2009a;
   MDH 2011).
   Based on the limited information available, fish
   and fishery products seem to be one of the
   primary sources of human exposure to PFOS. The
   maximum  permissible concentration (MPC), based
on consumption offish by humans as the most
critical route, is 0.65 nanograms per liter (ng/L) for
freshwater (Moermond et al. 2010).
Toxicology studies show that PFOS and PFOA are
readily absorbed after oral exposure and
accumulate primarily in the serum, kidney, and
liver. No further metabolism is expected (EFSA
2008; EPA 2006; EPA 2009a).
PFOS and PFOA have a long half-life of about 4
years in humans. This continued exposure could
increase body burdens to levels that would result
in adverse outcomes (ATSDR 2009; EPA 2009a).

  Emerging Contaminants Fact Sheet - PFOS and PFOA
What are the health effects of PFOS and PFOA? (continued)
   Acute- and intermediate- duration oral studies in
   rodents have raised concerns about potential
   developmental, reproductive, and other systematic
   effects of PFOS and PFOA (Austin et al. 2003;
   ATSDR 2009; EPA 2006).
   Results of a study indicate that exposure to PFOS
   can affect the neuroendocrine system in rats
   (Austin et al. 2003).
   Both PFOS and PFOA have a high affinity for
   binding to B-lipoproteins and liver fatty acid-
   binding protein. Several studies have shown that
   these compounds can interfere with fatty acid
   metabolism and may deregulate metabolism of
   lipids and lipoproteins (EFSA 2008; EPA 2009a).
   The EPA has not classified PFOS or PFOA as to
   carcinogenicity (ATSDR 2009).
The chronic exposure to PFOS and PFOA can
lead to the development of tumors in the liver of
rats; however, more research is needed to
determine if there are similar cancer risks for
humans (ATSDR 2009; OECD 2002).
Epidemiologic studies have shown an association
between PFOS exposure and bladder cancer;
however, further research is needed (EPA 2006;
OECD 2002).
The EPA is currently assessing PFOS to establish
the reference dose/reference concentration
(RfD/RfC), which will be made available to the
public through the Integrated Risk Information
System (IRIS) (EPA 2011b).
Are there any federal and state standards and guidelines
for PFOS and PFOA?
   The EPA has not established a minimal risk level
   (MRL) for PFOS or PFOA because human studies
   to date are insufficient to determine with a
   sufficient degree of certainty that the effects are
   either exposure-related or adverse (ATSDR 2009).
   The EPA finalized two Significant New Use Rules
   (SNURs) in 2002,  requiring companies to inform
   the EPA 90 days before they manufacture or
   import 88 identified PFOS-related substances
   (EPA 2008; UNEP2006).
   In 2007, the SNURs were amended to include 183
   additional PFOS-related substances with carbon
   chain lengths of five carbons and higher (EPA
   2006; UNEP 2007).
   The SNURs allow for the continuation of a few
   limited, highly technical uses of PFOS where there
   are no alternatives available, and which are
   characterized by very low volume, low exposure,
   and low releases (ATSDR 2009; EPA 2006).
   In January 2009, the EPA's Office of Water
   established a provisional health advisory (PHA) of
   0.2 micrograms per liter (ug/L) for PFOS and 0.4
   ug/L for PFOA to protect against the potential risk
from exposure of these chemical through drinking
water (EPA 2009b; EPA 2011 a).
EPA Region 4 recommended a residential soil
screening level of 6 milligrams per kilogram
(mg/kg) for PFOS and 16 mg/kg for PFOA (EPA
Minnesota has established a health risk limit of 0.3
ug/L for PFOS and PFOA in drinking water (MDH
New Jersey has established a preliminary
drinking-water guidance value of 0.04 ug/L for
PFOA (NJDEP 2007).
North Carolina has established an interim
maximum allowable concentration of 2 ug//L for
PFOA in drinking water (NCDENP 2008).
The EPA intends to propose actions in 2012 under
the Toxic Substances Control Act (TSCA) Section
6 to address the potential risks from long-chain
PFCs such as PFOS and PFOA. TSCA Section 6
provides authority for EPA to ban or restrict the
manufacture (including import), processing and
use of these chemicals (EPA 2009a).
What detection and site characterization methods are available for PFOS
and  PFOA?
   Detection methods for environmental samples are
   primarily based on high-performance liquid
   chromatography (HPLC) coupled with tandem
   mass spectrometry (MS/MS) (ATSDR 2009).
HPLC-MS/MS has allowed for more sensitive
determination of individual PFOS and PFOA in air,
water, and soil (ATSDR 2009).

  Emerging Contaminants Fact Sheet - PFOS and PFOA
What detection and site characterization methods are available for PFOS
and  PFOA? (continued)
   Both liquid chromatography (LC)-MS/MS and gas
   chromatography-mass spectrometry (GC-MS) can
   be used to identify the precursors of PFOS and
   PFOA (EFSA 2008).
   The development of LC - electrospray ionization
   (ESI) MS and LC-MS/MS has improved the
   analysis of PFOS and PFOA (EFSA 2008).
   Sample preparation methods include solvent
   extraction, ion-pair extraction, solid-phase
   extraction, and column-switching extraction
Air samples maybe collected using high-volume
air samplers that employ sampling modules
containing glass-fiber filters and glass columns
with a polyurethane foam (EFSA 2008).
Reported sensitivities for the available detection
methods include low picograms (pg) per cubic
meter (pg/m3) levels in air, high pg/L to low
nanogram (ng)/L levels in water, and high pg per
gram (pg/g) to low ng/g levels in soil (ATSDR
What technologies are being used to treat PFOS and PFOA?
   Because of their unique physiochemical properties
   (strong fluorine-carbon bond and low vapor
   pressure), PFOS and PFOA resist most
   conventional treatment technologies such as direct
   oxidation and biodegradation (Hartten 2009;
   Vectis et al. 2009).
   The optimal treatment method depends on the
   concentration of PFOS and PFOA, background
   organic and metal concentration, available
   degradation time, and other site-specific
   conditions (Vectis et al. 2009).
   Both activated carbon filters and reverse osmosis
   units have been shown to be effective at reducing
PFCs in water at levels typically found in drinking
water (below 0.2 ug/L); however, incineration of
the concentrated waste is required for complete
destruction of PFOS and PFOA (Hartten 2009;
MDH 2008; Vectis et al. 2009).
Alternative technologies studied for PFOS and
PFOA degradation include photochemical
oxidation and thermally-induced reduction (Hartten
2009; Vectis et al.  2009).
Studies have also  evaluated the use of
sonochemical degradation to treat PFOS and
PFOA in groundwater (Cheng et al 2008; Vectis et
al. 2009).
Where can I find more information about PFOS and PFOA?
   3M Company (3M). 2000. "Determination of serum
   half-lives of several fluorochemicals."

   Agency for Toxic Substance and Disease Registry
   (ATSDR). 2009. "Draft Toxicological Profile for

   Austin, M.E., Kasturi, B.S., Barber, M., Kannan,K.,
   MohanKumar, P.S., and MohanKumar, S.M. 2003.
   "Neuroendocrine effects of perfluorooctane
   sulfonate in rats." Environ Health Perspect.
   Volume 111(12). Pages 1485to1489.

   Brooke D., Footitt, A., and Nwaogu, T.A. 2004.
   Environmental Risk Evaluation Report:
   Perfluorooctane Sulfonate (PFOS).

   Cheng, J., Vecitis, C.D., Park, H., Mader, B.T.,
   and Hoffmann, M.R. 2008. Sonochemical
   Degradation of Perfluorooctane Sulfonate (PFOS)
   and Perfluorooctanoate (PFOA) in Landfill
Groundwater: Environmental Matrix Effects.
Environ. Sci. Technol. Volume 42 (21). Pages
8057 to 8063.

Conder, J.M., Wenning, R.J., Travers, M., and
Blom, M. 2010. Overview of the Environmental
Fate of Perfluorinated Compounds. Network for
Industrially Contaminated Land in Europe
(NICOLE) Technical Meeting. 4 November 2010.

Hartten, A.S. 2009. "Water Treatment of PFOA
and PFOS." DuPont Corporate Remediation

Minnesota Department of Health (MDH). 2008.
"MDH Evaluation of Point-of-Use Water Treatment
Devices for Perfluorochemical Removal. Final
Report Summary."

  Emerging Contaminants Fact Sheet - PFOS and PFOA
Where can I find  more information about PFOS and PFOA? (continued)
    MDH. 2011. Perfluorochemicals (PFCs) in

    Moermond, C., Verbruggem E., and Smit, C. 2010.
    Environmental risk limits for PFOS: A proposal for
    water quality standards in accordance with the
    Water Framework Directive.

    New Jersey Department of Environmental
    Protection (NJDEP). 2007. Determination of
    PerfluorooctanoicAcid (PFOA) in Aqueous
    Samples. Final Report.
    http://slic.nistatelib.org/slic files/diqidocs/w329/w3

    North Carolina Department of Environment and
    Natural Resources (NCDENP). 2008.
    Recommended Interim Maximum Allowable
    Concentration for PerfluorooctanoicAcid.

    Organization for Economic Cooperation and
    Development (OECD). Environment Directorate.
    2002. "Hazard Assessment of Perfluorooctane
    Sulfonate (PFOS) and its Salts."

    United National Environment Programme (UNEP).
    2005. "Perfluorooctane sulfonate proposal."
    Stockholm Convention on Persistent Organic
    Pollutants Review Committee. Geneva, 7-11
    November 2005.

    UNEP. 2006. "Risk profile on perfluorooctane
    sulfonate." Stockholm Convention  on Persistent
    Organic Pollutants Review Committee. Geneva,
    21 November 2006.

    UNEP. 2007." Risk Management Evaluation on
    Perfluorooctane Sulfonate." Stockholm Convention
    on Persistent Organic Pollutants Review
    Committee. Geneva, 19-23 2007.

    U.S. Department of Defense (DoD). 2011.
    Emerging Chemical & Material Risks.
U.S. Environmental Protection Agency (EPA).
2002. Hazard Assessment of Perfluorooctanoic
Acid and its Salts.
www.ewq.org/files/EPA hazard full.pdf

EPA. 2006. PFAS-Proposed Significant New Use
Rule, 40CFR721. U.S. Federal Register: Vol. 71
(No 47), March 10, 2006.

EPA. 2008. Significant new uses of chemical
substances. U.S. Environmental Protection
Agency. Code of Federal Regulations. 40 CFR

EPA. 2009a. Long-Chain Perfluorinated
Chemicals (PFCs) Action Plan.

EPA. 2009b. Provisional Health Advisories for
PerfluorooctanaoicAcid (PFOA) and
Perfluorooctyl Sulfonate (PFOS).

EPA Region 4. 2009c. Soil Screening Levels for
PerfluorooctanaoicAcid (PFOA) and
Perfluorooctyl Sulfonate (PFOS). Memorandum.

EPA. 2011 a. PerfluorooctanoicAcid (PFOA) and
Fluorinated Telomers. Related  EPA Actions.

EPA. 2011 b. Perfluorooctane Sulfonate (PFOS) -
IRIS Assessment.
http://cfpub.epa.gov/si/si public record report.cfm

EPA. 2012. Perfluorooctanoic acid (PFOA) and
Fluorinated Telomers. www.epa.gov/oppt/pfoa/

European Food Safety Authority (EFSA). 2008.
"Perfluorooctane sulfonate (PFOS),
Perfluorooctanoic acid (PFOA)  and their salts."
The EFSA Journal Volume 6 (53), Pages 1 to 131.

Vectis, C.D., Park, H., Cheng, J.,and Mader, B.T.
2009. "Treatment technologies  for aqueous
perfluorooctanesulfonate (PFOS) and
perfluorooctanoate (PFOA)." Frontiers of
Environmental Science & Engineering in China.
Volume 3(2), Pages 129 to151.
Contact Information
If you have any questions or comments on this fact sheet, please contact:  Mary Cooke, FFRRO, by phone at (703)
603-8712 or by email at cooke.marvt@epa.gov.