Additional Information in Relation to the Risk Management
Evaluation of PFOA, its Salts, and Related Compounds
prepared by ETH Zurich
on behalf of the Swiss Federal Office for the Environment (FOEN)
Table of Content
I. Additional information on chemical identity ...................................................................................... 2
II. Additional information regarding the transformation/degradation of fluorotelomers to PFOA ........ 5
III. Formation of PFOA from inadequate incineration of fluoropolymers ........................................... 12
IV. BAT/BEP in terms of emission control measures at industrial and firefighting training sites ...... 14
V. Additional information on alternatives to PFOA in fluoropolymer production .............................. 17
VI. Existing regulatory measures in China........................................................................................... 19
1
I. Additional information on chemical identity
Note: “Side-chain fluorinated polymers” are composed of variable non-fluorinated polymer backbones
with polyfluoroalkyl (and possibly perfluoroalkyl) side chains and are within the scope of PFOA-related
compounds when the length of the polyfluoroalkyl (and possibly perfluoroalkyl) side chains is equal to,
and greater than, 7 perfluorinated carbon atoms.
2
Note: Substances included in this figure are fluoropolymers (those made by (co)polymerization of olefinic monomers, at least one of which contains F bound
to one or both of the olefinic C atoms, to form a carbon-only polymer backbone with F atoms directly attached to it; Buck et al., 2011, doi: 10.1002/ieam.258)
and are outside the scope of PFOA-related compounds.
3
1. References
Banks RE, Smart BE, Tatlow JC. 1994. Organofluorine Chemistry – Principles and Commercial
Applications. Springer US, Springer Science+Business Media New York. doi: 10.1007/978-1-48991202-2
Buck RC, Franklin J, Berger U, Conder JM, Cousins IT, De Voogt P, et al. 2011. Perfluoroalkyl and
polyfluoroalkyl substances in the environment: terminology, classification, and origins. Integr
Environ Assess Manag. 7(4), 513–41.
Kissa, E., Fluorinated Surfactants and Repellents, 2 ed., Surfactant Science Series Vol. 97, Marcell
Dekker, New York, 2001. ISBN-13: 978-0824704728
4
II. Additional information regarding the transformation/degradation of fluorotelomers to PFOA
1. Fluorotelomer-based substances can be divided into three sub-groups: i) non-polymers with
simple molecules (e.g., FTIs, FTOs, FTOHs, FTSAs, etc.), ii) non-polymers with complex
molecules (e.g., fluorotelomer sterate monoesters or FTSs, FTABs, PAPs, etc.), and iii)
polymers. Substantial efforts have been made to study the degradation of the various sub-groups
of fluorotelomer-based substances. Such efforts are summarized in the following sub-sections;
for more details, one may consult the review articles Parsons et al. (2008), Young and Mabury
(2010), Liu And Avendaño (2013), Butt et al. (2014) and references therein.
i) transformation of simple molecules to PFOA
2. The transformation of fluorotelomer-based substances with simple molecules in air, water and
soil (including activated sludge) has been extensively studied and they may undergo distinct
transformation processes and thus transform into different products with different yields,
depending on the medium and conditions (as reviewed in Young and Mabury (2010) and Liu and
Avenañdo (2013)). For instance, Gauthier and Mabury (2005) studied the indirect photolysis of
8:2 FTOH in water and found that in natural water obtained from Lake Ontario, the half-life was
93.2±10.0 h and the PFOA yield was approximately 7%. Since 8:2 FTOH has a high air-water
partition coefficient (KAW) (Goss et al., 2006) and also a rather high sorption to organic phases
(Liu and Lee, 2007), it is likely that only a negligible amount of FTOHs in the environment
undergoes indirect photolysis in water and forms PFCAs. The majority of FTOHs in water is
either vaporized and forms PFCAs through OH radical oxidation in the atmosphere or is
accumulated in the organic phase and forms PFCAs through microbial transformation. Hence,
here we focus on the atmospheric (through OH radical) and biotic transformation (in soils and
activated sludge) that is mostly relevant for the levels of PFOA formed in the environment, as
most of the species with small molecules have either relatively high KAW or rather high sorption
to organic phase or both (Z Wang et al., 2011).
3. Smog chamber studies showed that FTOs, FTIs, FTOHs and FTACs undergo perfluorocarbonchain-length-independent OH radical-mediated oxidation, even in the presence of NOX (<40 ppb,
which encompasses all but highly polluted urban conditions), and form fluorotelomer aldehydes
(FTALs) or perfluoroalkyl aldehydes (PFALs) that can be further oxidized to PFCAs in the
atmosphere (detailed mechanisms, pathways and products of these atmospheric degradation have
been summarized in a review by Young and Mabury (2010) and are illustrated in Figure 1). In
particular, the perfluorinated carbon chain of the parent substances can be shortened during the
atmospheric transformation (see the orange box in Figure 1); for more details, see Young and
Mabury (2010). For example, yields of PFNA (1.6 mol%), PFOA (1.5 mol%), PFHpA (0.32
mol%), PFHxA (0.24 mol%) and PFPeA (0.1 mol%) were identified after 94 mol% conversion
of 8:2 FTOH, respectively (Ellis et al., 2004). Considering that many intermediates that may
yield additional PFCAs upon further oxidation were also observed in the investigated samples,
the actual yields are likely higher than the observed ones in Ellis et al. (2004). Similarly, PFCAs
with 1–4 perfluorinated carbon atoms were observed in the smog chamber study of 4:2 FTI
(Young et al., 2008).
4. On the other hand, studies on the biodegradation of FTOHs in soil and activated sludge as well
as FTSAs in activated sludge show similar shortening of the perfluorinated carbon chain, but
may result in different homologue distribution of PFCAs as end products (see Table 1). For
example, FTOHs undergoing biodegradation form no PFNA (in the case of 8:2 FTOH) and no
PFHpA (in the case of 6:2 FTOH) in contrast to OH radical oxidation in air (see Table 1). Liu
and Avenañdo (2013) noted that not all microbial degradation pathways of FTOH lead to PFOA,
and each pathway has its own rate constant, which may be dependent on concentration, the types
of microbial communities, and other soil factors. In some cases, certain reactions could be
reversible. In addition, the irreversible binding of degradation products to soil (presumably soil
organic matter) over time will also affect PFOA production.
5
5. Based on the existing scientific evidence, it can be drawn that both abiotic and biotic
transformation mechanism is not influenced by the perfluorinated carbon chain length, and when
a fluorotelomer-based substance degrades, the transformation products include several PFCA
homologues with shorter perfluoroalkyl chain, and sometimes also the PFCA homologues with
the same perfluorinated carbon chain length (e.g., in the case of abiotic degradation). Thus, 8:2
and longer-chain fluorotelomer substances may transform to PFOA in the environment and biota,
although the yields of PFOA from the transformation may be different for different homologues,
depending on their perfluorinated carbon chain length.
Figure 1. Degradation scheme of FTOH and POSF-based precursors in the atmosphere, reproduced
from Schenker et al. (2008). Summary of the key reactions; some arrows represent a series of reactions;
R1, methyl or ethyl; R2 – R4, various substituents of intermediate degradation products.
Table 1. Measured PFCA yields in biodegradation studies, in mol% of the amount of the parent product.
Microbial = bacterial culture; N.M. = not measured; N.D. = not detected; N.Q. = not quantifiable; N.A. =
not applicable; N.R. = not reported.
Parent
Remain PFBA PFPeA PFHxA PFHpA
Medium Time
compound
-ing
(C4)
(C5)
(C6)
(C7)
8:2 FTOH
microbial 81 d
55%
N.M.
N.M.
N.M.
N.D.
8:2 FTOH
microbial 90 d
36%
N.M.
N.M.
0.9%
N.M.
8:2 FTOH
soil
7 d 20–50% N.M.
N.M.
< 1%
< 1%
8:2 FTOH
microbial 67 d
N.R.
N.M.
N.M.
> 0.1% < 0.01%
8:2 FTOH
3 soils *
N.M.
N.M.
> 4%
N.M.
6:2 FTOH
soil
84 d
86%
0.8%
4.2%
4.5%
N.D.
6:2 FTOH
soil
180 d
3%
2%
30%
8%
N.D.
6:2 FTOH
microbial 90 d
< 3%
< 0.5% < 0.5%
5%
N.D.
6:2 FTSA
sludge
90 d
> 24% 0.14%
1.5%
1.1%
N.D.
6:2 FTOH
microbial 28 d
N.R.
0.44%
N.R.
2.8%
N.R.
8:2 FTOH
microbial 28 d
N.R.
N.R.
N.R.
0.62%
N.R.
10:2 FTUCA sediment 35 d
0.62%
N.M.
N.M.
N.R.
0.37%
PFOA
(C8)
3%
6%
< 1%
0.1–1%
25%
N.A.
N.A.
N.A.
N.A.
N.A.
2.6%
1.9%
PFNA PFDA
Reference
(C9)
(C10)
N.D.
N.A.
Dinglasan et al., 2004
N.D.
N.A.
Wang et al., 2005
N.Q.
N.A.
Liu et al., 2007
N.Q.
N.A.
Liu et al., 2010
N.D.
N.A.
Wang et al., 2009
N.A.
N.A.
Liu et al., 2010
N.A.
N.A.
Liu et al., 2010
N.A.
N.A.
Liu et al., 2010
N.A.
N.A.
N Wang et al., 2011
N.A.
N.A.
Kim et al., 2012
N.R.
N.A.
Kim et al., 2012
1.7%
28% Myers and Mabury, 2010
* The authors tested the biodegradation of 8:2 FTOH in three types of soil with different time spans. The
yield of PFOA listed here is the average value.
6
ii) degradation of complex molecules to simple molecules, then to PFOA
4. The break down of fluorotelomer-based substances with complex molecules to those with simple
molecules follows the convention organic chemistry, e.g., hydrolysis of ester bonds, supported
by the following studies that have reported the biodegradation of a wide range of fluorotelomerbased substances with complex molecules to molecules with simpler structures.
Parent product
C8F17CH2CH2OC(O)CH=CH2
(8:2 fluorotelomer acrylate, 8:2 FTAC)
Transformation
product
C8F18CH2CH2OH
(8:2 FTOH)
C8F17CH2CH2OC(O)C(CH3)=CH2
(8:2 fluortelomer methacrylate, 8:2 FTMAC)
(CnF2n+1CH2CH2O)2PO2H
(n:2 diPAP)
C8F18CH2CH2OH
(8:2 FTOH)
CnF2n+1CH2CH2OH
(n:2 FTOH)
C8F17CH2CH2OC(O)C17H35
(8:2 fluorotelomer stearate monoester; 8:2 FTS)
C8F18CH2CH2OH
(8:2 FTOH)
[C8F17CH2CH2OC(O)CH2]2C(OH)[C(O)OCH2CH2C8F17]
(8:2 fluorotelomer citrate triester, 8:2 TBC)
Toluene-2,4-di(8:2 fluorotelomer urethane) /
hexamethylene-1,6-di(8:2
fluorotelomer
urethane) monomers
CnF2n+1CH2CH2SCH2CH2C(O)NHCH(CH3)2CH2SO3H
(n:2 fluorotelomer thioether amido sulfonate,
n:2 FTTAoS)
C8F18CH2CH2OH
(8:2 FTOH)
C8F18CH2CH2OH
(8:2 FTOH)
CnF2n+1CH2CH2SO3H
(n:2 FTSA)
+ CnF2n+1CH2CH2OH
(n:2 FTOH)
References
Royer et al. (2015):
using aerobic soils for 105 days;
Butt et al. (2010):
using in vitro S9 hepatic and stomach
fractions
Royer et al. (2015):
using aerobic soils for 105 days
D’eon and Mabury (2007):
degradation of 6:2 diPAP using
Sprague-Dawley rats;
Lee et al. (2010):
degradation of 4:2, 6:2 and 8:2
diPAPs using a mixture of raw
wastewater and sewage sludge for 92
days;
Lee et al. (2013):
degradation of 6:2 diPAP in
biosolids-applied soil;
Lewis et al. (2016):
degradation of 6:2 diPAP using three
Pseudomonas strains under different
co-substrate conditions and activated
sludge;
Bizkarguenaga et al. (2016):
degradation of 8:2 diPAP using two
different amended soils with and
without lettuce or carrot;
Liu and Liu (2016):
degradation of 6:2 and 8:2 diPAPs
using aerobic soil
Dasu et al. (2012):
using aerobic soils for 80 days;
Dasu et al. (2013):
using a forest soil in closed bottle
microcosms
Dasu et al. (2013):
using a forest soil in closed bottle
microcosms
Dasu and Lee (2016):
using one forest soil (FRST-44) for
117 and 180 days, respectively
Weiner et al. (2013):
degradation of 6:2 FTTAoS using
aerobic wastewater treatment plant
sludge;
Harding-Marjanovic et al. (2015):
degradation of 4:2, 6:2 and 8:2
FTTAoSs using medium microcosms
amended with an aqueous filmforming foam solution
7
5. In addition, two studies have observed the partial breakdown of the functional groups, but have
not observed substances such as FTOHs and FTSAs (Frömel and Knepper, 2010; Moe et al.,
2012); this is likely that the experimental duration was not long enough, as also stated by the
authors. Hence, it can be expected that most, if not all, 8:2 and longer-chain fluorotelomer-based
substances with complex structures may (bio)degrade and form molecules with simpler
structures (which are PFOA precursors as elaborated above), although the degradation half-lives
may vary considerably among substances.
iii) (bio)degradation of side-chain fluorinated polymers
6. All available studies from industrial, regulatory and academic scientists have reported the
degradation of fluorotelomer-based side-chain fluorinated polymers (e.g., fluorotelomer-based
acrylate polymers and urethane polymers) to corresponding PFCA precursors (such as FTOHs)
biotically in aerobic soils (Russell et al., 2008, 2010a; Washington et al., 2009, 2014; Rankin et
al., 2014) and abiotically in water (Washington et al., 2014, 2015). A reliable estimation of the
amount of PFOA from (bio)degradation of fluorotelomer-based side-chain fluorinated polymers
within the current time frame (years to decades) is not yet possible, mainly because there is high
uncertainty in the degradation half-lives (ranging from decades up to millennia) (Russell et al.,
2008, 2010a, b; Washington et al., 2009, 2010, 2014, 2015; Rankin et al., 2014), which is mostly
due to the significant challenges associated with measuring such low degradation rate. It is also
unknown to what extent laboratory conditions represent the real environment (in terms of
temperature, microbial community, the change of crystal structure and thus bioavailability of
polymers over time, co-existence of other substances, etc.). In addition, many other types of sidechain fluorinated polymers than the ones tested are produced (Buck et al., 2011).
7. However, it should be noted that in a long-term, all fluorotelomer-based side-chain fluorinated
polymers that are not properly treated (e.g., high temperature incineration) will eventually be
degraded to PFCA precursors; some of these precursors may further degrade to form PFOA in
the environment and biota, as elaborated above. Thus, (bio)degradation of 8:2 and longer-chain
fluorotelomer-based side-chain fluorinated polymers may act as a long-term source of PFOA in
the environment and biota. Considering the vast amounts of long-chain fluorotelomer-based
side-chain fluorinated polymers that have been produced in the past and may be still produced in
some countries (see above), (bio)degradation of these polymers can be a substantial source of
PFOA in the environment in the long run. Future studies can focus on understanding how the
different physical and physicochemical properties of these side-chain fluorinated polymers may
influence the bioavailability and thus the time scale of (bio)degradation, as well as the amounts
and types of side-chain fluorinated polymers produced, used and emitted in the environment.
8. References
Bizkarguenaga E, Zabaleta I, Prieo A, Fernández LA, Zuloaga. 2016. Uptake of 8:2 perfluoroalkyl
phosphate diester and its degradation products by carrot and lettuce from compost-amended soil.
Chemosphere 152, 309-317.
Buck RC, Franklin J, Berger U, Conder JM, Cousins IT, De Voogt P, et al. 2011. Perfluoroalkyl and
polyfluoroalkyl substances in the environment: terminology, classification, and origins. Integr
Environ Assess Manag. 7(4), 513–41.
Butt CM, Muir DCG, Mabury SA. 2010. Biotransformation of the 8:2 fluorotelomer acrylate in
rainbow trout. 2. In vitro incubation with liver and stomach S9 fractions. Environ Toxicol Chem 29,
2736-2741.
Butt CM, Muir DCG and Mabury SA. 2014. Biotransformation pathways of fluorotelomer-based
polyfluoroalkyl substances: A review. Environ Toxicol Chem, 33: 243–267. doi:10.1002/etc.2407
8
D’eon JC, Hurley MD, Wallington TJ, Mabury SA. 2006. Atmospheric chemistry of N-methyl
perfluorobutane sulfonamidoethanol, C4F9SO2N(CH3)CH2CH2OH: kinetics and mechanism of
reaction with OH. Environ Sci Technol. 40, 1862-1868.
D’eon JC, Mabury SA. 2007. Production of perfluorinated carboxylic acids (PFCAs) from the
biotransformation of polyfluoroalkyl phosphate surfactants (PAPs): exploring routes of human
contamination. Environ Sci Technol. 41, 4799-4805.
Dasu K, Liu J, Linda LS. 2012. Aerobic soil biodegradation of 8:2 fluorotelomer stearate monoester.
Environ Sci Technol. 46, 3831-3836.
Dasu K, Lee LS, Turco RF, Nies LF. 2013. Aerobic biodegradation of 8:2 fluorotelomer stearate
monoester and 8:2 fluorotelomer citrate trimester in forest soil. Chemosphere 91, 399-405.
Dasu K, Lee LS. 2016. Aerobic biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) and
hexmethylene-1,6-di(8:2 fluorotelomer urethane) monomers in soils. Chemosphere 144, 2482-2488.
Dinglasan MJA, Ye Y, Edwards EA, Mabury SA. 2004. Fluorotelomer alcohol biodegradation yields
poly- and perfluorinated acids. Environ Sci Technol 38, 2857–2864.
Ellis DA, Martin JW, De Silva AO, Mabury SA, Hurley MD, Sulbaek Andersen MP, Wallington TJ.
2004. Degradation of fluorotelomer alcohols: a likely atmospheric source of perfluorinated
carboxylic acids. Environ Sci Technol 38, 3316–3321.
Frömel T, Knepper TP. 2010. Fluorotelomer ethoxylates: sources of highly fluorinated environmental
contaminants part I: Biotransformation. Chemosphere 80, 1387-1392.
Gauthier SA, Mabury SA. 2005. Aqueous photolysis of 8:2 fluorotelomer alcohol. Environ Toxicol
Chem 24, 1837–1846.
Goss KU, Bronner G, Harner T, Hertel M, Schmidt TC. 2006. The partition behavior of
fluorotelomer alcohols and olefins. Environ Sci Technol 40, 3572–3577.
Harding-Marjanovic KC, Houtz EF, Yi S, Field JA, Sedlak DL, Alvarz-Cohen L. 2015. Aerobic
biotransformation of fluorotelomer thioether amido sulfonate (Lodyne) in AFFF-amended
microcosms. Environ Sci Technol. 49, 7666-7674.
Kim MH, Wang N, McDonald T, Chu KH. 2012. Biodefluorination and biotransformation of
fluorotelomer alcohols by two alkane-degrading Pseudomonas strains. Biotechnol. Bioeng. 109,
3041–3048.
Lee H, D’eon J, Mabury SA. 2010. Biodegradation of polyfluoroalkyl phosphate as a source of
perfluorinated acids to the environment. Environ Sci Technol. 44, 3305-3310.
Lee H, Tevlin AG, Mabury SA, Mabury SA. 2013. Fate of polyfluoroalkyl phosphate diesters and
their metabolites in biosolids-applied soil: biodegradation and plant uptake in greenhouse and field
experiments. Environ Sci Technol. 48, 340-349.
Lewis M, Kim MH, Liu EJ, Wang N, Chu KH. 2016. Biotransformation of 6:2 polyfluoroalkyl
phosphates (6:2 PAPs): effects of degradative bacteria and co-substrates. J Hazard Mater. In press.
doi: 10.1016/j.jhazmat.2016.08.036.
Liu C, Liu J. 2016. Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil.
Environ Poll. 212, 230-237.
Liu J, Lee LS. 2007. Effect of fluorotelomer alcohol chain length on aqueous solubility and sorption
by soils. Environ Sci Technol 41, 5357–5362.
Liu J, Lee LS, Nies LF, Nakatsu CH, Turcot RF. 2007. Biotransformation of 8:2 fluorotelomer
alcohol in soil and by soil bacteria isolates. Environ Sci Technol 41, 8024–8030.
Liu J, Wang N, Szostek B, Buck RC, Folsom PW, Sulecki LM, Bellin CA. 2010. 6-2 Fluorotelomer
alcohol aerobic biodegradation in soil and mixed bacterial culture. Chemosphere 78, 437–444.
Liu J, Avendaño SM. 2013. Microbial degradation of polyfluoroalkyl chemicals in the environment:
a review. Environ Int, 61, 98-114.
9
Moe MK, Huber S, Svenson J, Hagenaars A, Pabon M, Trümper M, et al. 2012. The structure of the
fire fighting foam surfactant Forafac® 1157 and its biological and photolytic transformation
products. Chemosphere 89, 869-875.
Myers AL and Mabury SA. (2010), Fate of fluorotelomer acids in a soil–water microcosm. Environ
Toxicol Chem, 29: 1689–1695. doi:10.1002/etc.211
Parsons JR, Sáez M, Dolfing J, De Voogt P. 2008. Biodegradation of Perfluorinated Compounds. In
Reviews of Environmental Contamination and Toxicology Vol 196; Whitacre, D. M., Ed.; Reviews
of Environmental Contamination and Toxicology Vol 196; Springer US: New York, NY. pp 53–71.
doi: 10.1007/978-0-387-78444-1_2
Rankin K, Lee H, Tseng PJ, Mabury SA. 2014. Investigating the biodegradability of a fluorotelomerbased acrylate polymer in a soil-plant microcosm by indirect and direct analysis. Environ Sci Technol
48, 12783-12790.
Royer LA, Lee LS, Russell MH, Nies LF, Turco RF. 2015. Microbial transformation of 8:2
fluorotelomer acrylate and methacrylate in aerobic soils. Chemosphere 129, 54-61.
Russell MH, Berti WR, Szostek B, Buck RC. 2008. Investigation of the biodegradation potential of a
fluoroacrylate polymer product in aerobic soils. Environ Sci Technol 42, 800–7.
Russell MH, Wang N, Berti WR, Szostek B, Buck RC. 2010a. Comment on “Degradability of an
acrylate-linked fluorotelomer polymer in soil.” Environ Sci Technol 44, 848.
Russell MH, Berti WR, Szostek B, Wang N, Buck RC. 2010b. Evaluation of PFO formation from the
biodegradation of a fluorotelomer-based urethane polymer product in aerobic soils. Polym Degrad
Stabil 95, 79–85.
Schenker U, Scheringer M, MacLeod M, Martin J, Cousins IT, Hungerbühler K. 2008. Contribution
of volatile precursor substances to the flux of perfluorooctanoate to the Arctic. Environ Sci Technol.
42, 3710-3716.
Wang N, Szostek B, Buck RC, Folsom PW, Sulecki LM, Capka V, Berti WR, Gannon JT. 2005.
Fluorotelomer alcohol biodegradation-direct evidence that perfluorinated carbon chains breakdown.
Environ Sci Technol 39, 7516–7528.
Wang N, Szostek B, Buck RC, Folsom PW, Sulecki LM, Gannon JT. 2009. 8-2 fluorotelomer alcohol
aerobic soil biodegradation: pathways, metabolites, and metabolite yields. Chemosphere 75, 1089–
1096.
Wang N, Liu J, Buck RC, Korzeniowski SH, Wolstenholme BW, Folsom PW, Sulecki LM. 2011. 6:2
fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants.
Chemosphere 82, 853–858
Wang N, Buck RC, Szostek B, Sulecki LM, Wolstenholme BW. 2012. 5:3 Polyfluorinated acid
aerobic biotransformation in activated sludge via novel "one-carbon removal pathways".
Chemosphere 87, 527–534.
Wang Z, MacLeod M, Cousins IT, Scheringer M, Hungerbuehler K. 2011. Using COSMOtherm to
predict physicochemical properties of poly- and perfluorinated alkyl substances (PFASs). Environ
Chem 8, 389–398.
Washington JW, Ellington J, Jenkins TM, Evans JJ, Yoo H, Hafner SC. 2009. Degradability of an
acrylate-linked fluorotelomer polymer in soil. Environ Sci Technol 43, 6617–23.
Washington JW, Ellington JJ, Jenkins TM, Yoo H. 2010. Response to comments on “Degradability
of an acrylate-linked fluorotelomer polymer in soil.” Environ Sci Technol 44, 849–50.
Washington JW, Thomas MJ, Rankin K, Naile JE. 2014. Decades-scale degradation of commercial,
side-chain, fluorotelomer-based polymers in soils and water. Environ Sci Technol. 49, 915-923.
Washington JW, Jenkins TM. 2015. Abiotic hydrolysis of fluorotelomer-based polymers as a source
of perfluorocarboxylates at the global scale. Environ Sci Technol. 49, 14129-14135.
10
Weiner B, Yeung LWY, Marchington EB, D’Agostino LA, Mabury SA. 2013. Organic fluorine
content in aqueous film forming foams (AFFFs) and biodegradation of the foam component 6:2
fluorotelomermercaptoalkylamido sulfonate (6:2 FTSAS). Environ Chem, 10, 486-493.
Young CJ, Hurley MD, Wallington TJ, Mabury SA. 2008. Atmospheric Chemistry of 4:2
Fluorotelomer Iodide (n-C4F9CH2CH2I): Kinetics and Products of Photolysis and Reaction with OH
Radicals and Cl Atoms. J Phys Chem A 112(51), 13542-13548.
Young CJ, Mabury SA. 2010. Atmospheric perfluorinated acid precursors: chemistry, occurrence,
and impacts. Rev Environ Contam Toxicol 208, 1–109
11
III. Formation of PFOA from inadequate incineration of fluoropolymers
1. An indirect source of PFOA may be inadequate incineration of fluoropolymers and other highly
fluorinated polymers. For example, at temperatures above 260 °C, PTFE starts to break down.
The transformation products are predominantly monomers with varied chain lengths (C2F4, C3F6,
c-C4F8, etc.) (Lewis and Naylor, 1947; Simon and Kaminsky, 1998; Ellis et al., 2001, 2003;
García et al., 2007; Odochian et al., 2011; Puts et al., 2014). Some recent studies qualitatively
show that small, but measurable amounts of PFOA and a wide range of other PFCA homologues
can also be generated during the thermolysis of non-functionalized PTFE (Ellis et al., 2001,
2003; Schlummer, 2015) and functionalized PTFE (Feng et al., 2015) at temperatures between
250 °C and 600 °C (see Table 2). The exact mechanisms for the formation of PFCAs have not
been fully understood yet. However, it has been postulated that the thermolysis of some
fluoropolymers such as PTFE generate radicals including :CF2 and ・CF2(CF2)nCF2・(Ellis et
al., 2001; Odochian et al., 2011; Puts et al., 2014; Feng et al., 2015), which can further react with
other radicals and water vapour to generate PFCAs (Ellis et al., 2001; Young and Mabury, 2010;
Feng et al., 2015).
Table 2. Observations of PFCA generations during the thermolysis of PTFE.
Fluoropolymer
PTFE (2g)
PTFE (2g)
PTFE (unknown*)
Nafion N117 ** (0.5 g)
Maximum temperature
360 °C; 500 °C
300 °C; 500 °C
250°C; 300 °C; 370 °C
600 °C
PFCA observed
C2–C13 PFCAs
C2–C14 PFCAs
C4–C12 PFCAs
C2–C19 PFCAs
References
Ellis et al., 2001
Ellis et al., 2003
Schlummer, 2015
Feng et al., 2015
* The authors used PFOA-free PTFE-coated cooking pans in their experiments; the amounts of
PTFE coatings were not measured.
** Nafion N117 is a polymer consisting of a PTFE backbone with perfluoroalkylether pendant
chains terminating in sulfonic acid groups.
2. In 2005, the US EPA and four major fluoropolymer and fluoroelastomer producers (Asahi,
Daikin, Dyneon and DuPont) reached an enforceable consent agreement (ECA) for a laboratoryscale incineration testing on fluoropolymers (US EPA, 2005). To date, the US EPA has not yet
published the final report of the ECA. Results from an industry-sponsored study suggested that
waste incineration of fluoropolymers does not emit detectable levels of PFOA under conditions
representative of typical municipal waste combustor operations in the US
(～1000 °C; Taylor,
2009). Similarly, no formation of PFOA was observed in the off-gases from the combustion of
some polyester/cellulose fabric treated with one type of fluorotelomer-based acrylate polymers at
1000 °C (Yamada et al., 2005).
3. Therefore, substantial releases of PFOA during cooking with PTFE-coated pans are unlikely at
normal cooking temperatures (<230 °C) (Imbalzano, 1991; Schlummer et al., 2015), nor at
municipal incinerators with temperatures at 1000 °C or greater.
4. It is currently unclear to what extent such formation of PFOA may occur in municipal waste
incinerators where (i) flue gases may reach temperatures of 850 °C or greater (e.g., in the
European Union, according to the EU Directive 2000/76/EC) and may result in different
degradation products (García et al., 2007); (ii) other substances coexist and may interfere with
the thermolysis of fluoropolymers (e.g., thermolysis of PTFE is inhibited by a hydrogen or
chlorine atmosphere in contrast to steam, oxygen or sulfur dioxide, which accelerate
decomposition; Simon and Kaminsky, 1998); and (iii) technologies such as activated carbon
injection (ACI) coupled with baghouse filtration (BF) may be installed to remove dioxin or
mercury and may also trap PFCAs (EU Commission, 2006). However, a recent study found
PFOA in the flue gases from the incinerator of Harlingen, the Netherlands (Arkenbout, 2016).
12
5. Furthermore, such thermally induced transformations of fluoropolymers and other highly
fluorinated polymers to PFOA and its homologues may well occur at incinerators or open
burning facilities where temperatures are between 250 °C and 600 °C (at least). This may be
particularly critical for developing countries and countries with economies in transition, where
wastes are often not incinerated to high temperatures and without proper treatment of flue gases
due to a lack of adequate facilities.
6. References
Arkenbout A. 2016. Biomonitoring and source tracking of dioxins in the Netherlands. Organohalogen
Compounds Vol. 78, 352–355.
Ellis DA, Mabury SA, Martin JW, Muir DCG. 2001. Thermolysis of fluoropolymers as a potential
source of halogenated organic acids in the environment. Nature 412, 321–4.
Ellis DA, Martin JW, Muir DCG, Mabury SA. 2003. The use of 19F NMR and mass spectrometry for
the elucidation of novel fluorinated acids and atmospheric fluoroacid precursors evolved in the
thermolysis of fluoropolymers. Analyst 128, 756–764. Doi: 10.1039/b212658c.
EU Commission (European Commission). 2006. Reference document on the best available
techniques for waste incineration. Brussels. http://eippcb.jrc.ec.europa.eu/reference/
Feng M, Qu R, Wei Z, Wang L, Sun P, Wang Z. 2015. Characterization of the thermolysis products
of Nafion membrane: a potential source of perfluorinated compounds in the environment. Sci Rep. 5,
9859. doi: 10.1038/srep09859
García A. N, Viciano N, Font R. 2007. Products obtained in the fuel-rich combustion of PTFE at high
temperature. J Anal Appl Pyrolysis 80, 85–91.
Imbalzano JF. 1991. Combat corrosion with fluoroplastics and fluoroelastomers. Chem Eng Progr 87,
69–73.
Lewis EE, Naylor MA. 1947. Pyrolysis of polytetrafluoroethylene. J Am Chem Soc 69, 1968–70.
Schlummer M, Sölch C, Meisel T, Still M, Gruber L, Gerd W. 2015. Emission of perfluoroalkyl
carboxylic acids (PFCA) from heated surfaces made of polytetrafluoroethylene (PTFE) applied in
food contact materials and consumer products. Chemosphere 129, 46-53.
Odochian L, Moldoveanu C, Mocanu AM, Carja G. 2013. Contributions to the thermal degradation
mechanism under air atmosphere of PTFE by TG–FTIR analysis: Influence of the additive nature.
Thermochimica Acta, Volume 558, 20 April 2013, Pages 22-28, doi: 10.1016/j.tca.2013.02.008.
Puts G, Crouse P, Ameduri B. 2014. Thermal Degradation and Pyrolysis of Polytetrafluoroethylene,
in Handbook of Fluoropolymer Science and Technology (eds D. W. Smith, S. T. Iacono and S. S.
Iyer), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118850220.ch5
Simon CM, Kaminsky W. 1998. Chemical recycling of polytetrafluoroethylene by pyrolysis. Poly
Degrad Stabil 62, 1–7.
Taylor PH. 2009. ECA incineration testing program: laboratory-scale incineration testing of
fluoropolymers; University of Dayton Research Institute. Pp. 1–84.
US EPA (United States Environmental Protection Agency). 2005. Final enforceable consent
agreement and testing consent order for four formulated composites of fluoropolymer chemicals;
export notification. Federal Register 70, 39630–7.
Yamada T, Taylor PH, Buck RC, Kaiser MA, Giraud RJ. 2005. Thermal degradation of
fluorotelomer treated articles and related materials. Chemosphere 61, 974–84.
13
IV. BAT/BEP in terms of emission control measures at industrial and firefighting training sites
1. A number of fluoropolymer and fluoroelastomer producers in many parts of the world have
developed and implemented various technologies to recover and recycle PFOA and other
fluorinated emulsifiers from their production process, including treatment of off-gases,
wastewater streams, and fluoropolymer dispersions, so as to reduce emissions and exposure to
them (US EPA, 2003; Feng and Su, 2007; Tang et al., 2009; Hintzer and Schwertfeger, 2014 and
references therein). These technologies are summarized in the following. Some of these
technologies may also be used to treat waste streams and products of other relevant industries to
reduce emissions and exposure of PFOA and related compounds.
Treatment of off-gases: PFOA or its salts may be removed from off-gases by scrubbing such
gases with aqueous NaOH (Sulzbach et al., 1999) and K2CO3 solutions (Sulzbach et al., 2001).
Later on, recycling of the PFOA may be achieved by acidification of the mixture followed by
esterification, distillation, and finally conversion of the pure ester to the ammonium salt APFO
(Obermeier and Stefaniak, 1997). Examples of producers from developing and transition
countries that have developed such technologies include Shandong Dongyue (Yu et al., 2008).
Treatment of wastewater streams: PFOA or its salts may be removed from effluents by first
adding small amounts of a non-ionic emulsifier to the wastewater stream (Felix et al., 2003;
Hintzer et al., 2006) and then passing through strongly basic anion exchange resin bed (Kuhls
and Weiss, 1983; Felix et al., 2003) or granulated active carbon (GAC) bed (Hintzer et al.,
2006). The loaded anion exchange resins and GAC may be re-generated and re-used through
various technologies, and PFOA or its salts may be collected for recycling or disposal (for
details, see Hintzer and Schwertfeger, 2014 and references therein). Examples of producers from
developing and transition countries that have developed (and implemented) such technologies
include Shandong Dongyue (Sun et al., 2008) and Zhonghao Chenguang (since 2002, reduction
of emissions of PFOA by 75% or greater; Xie et al., 2009)
Treatment of fluoropolymer dispersions: Similarly to treatment of wastewater streams, the
majority of PFOA or its salts may be removed from fluoropolymer dispersions by using strongly
basic anion exchange resins (in the form of a fixed bed (Blädel et al., 2004) or non-fixed form
(Combes et al., 2010)) with the presence of non-ionic non-fluorinated emulsifiers to stabilize the
dispersions. The loaded anion exchange resins may be re-generated and re-used through various
technologies, and PFOA or its salts may be collected for recycling or disposal (for details, see
Hintzer and Schwertfeger, 2014 and references therein). Alternatively, aqueous solutions can
also be treated through several other technologies such as ultrafiltration using oscillating
membranes (Britnell et al., 2006), thermal degradation of the emulsifiers at sufficiently high
temperatures (Johnson and Teter, 2010), or in a flow reactor using a catalyst bed consisting of
metal oxides (Nomura and Matsuoka, 2010). Examples of producers from developing and
transition countries that have developed and implemented such technologies include Zhonghao
Chenguang (reduction to 100 ppm; Xie et al., 2009), Shanghai 3F (reduction of PFOA content by
95% to 40 ppm; Feng and Su, 2007).
2. In 2014, Fluorocouncil published “Guidance for Best Environmental Practices (BEP) for the
Global Apparel Industry – including focus on fluorinated repellent products” (Fluorocouncil,
2014). The guidance recommends a set of basic actions in the following schematic areas for BEP
of fluorinated DWR products: 1) raise environmental awareness with all employees; 2) follow
advice of the Safety Data Sheet (SDS) and Technical Data Sheet (TDS) for the product; 3) use
the product only if necessary to obtain effects desired; 4) use only what you need: work with the
chemical supplier to set the amount; 5) mix only what will be used in the scheduled run; 6)
schedule runs to avoid bath changes and wasted liquors; 7) reuse/recycle residual liquors/surplus
of liquors if this can be done without jeopardizing quality; 8) maintain all equipment in excellent
working condition and conduct periodic operations audits; 9) optimize drying and curing
conditions in the stenter frame; 10) dispose of chemicals appropriately; 11) consider additional
14
opportunities to minimize waste and emissions.
3. The Fire Fighting Foam Coalition has published “Best Practice Guidance for Use of Class B
Firefighting Foams” that includes guidance on proper foam selection, containing and eliminating
foam discharge, and disposal of foam and firewater (FFFC, unknown). Among others, it recommends
the use of training foams that do not contain fluorosurfactants for training purposes.
4. References
Blädel H, Hintzer K, Löhr G, Schwertfeger W, Sulzbach RA. 2004. Patent: Aqeuous dispersions of
fluoropolymers. Patent No. US 6833403 B1
Britnell A, Simpson M, Conheady J, Hosokawa K. 2006. Patent: Method of concentrating
fluoropolymer and fluorine-containing emulsifiers. Patent No. US 20060241214 A1.
Combes JR, Johnson DW, Breske ST. 2010. Patent: Removing fluorosurfactant from aqueous
fluoropolymer dispersions using anion exchange polymer with functional groups resistant to
degradation to trialkyl amines. Patent No. US 20100093894 A1.
Felix B, Zipplies T, Führer S, Kaiser T, Budesheim A. 2003. Patent: Process for the recovery of
fluorinated alkandic acids from wastewater. Patent No. US 6518442 B1
Feng D, Su X. 2007. Trend on the PFOA in fluorinated applications. New Chemical Materials. S1.
[in Chinese]. Available from: http://en.cnki.com.cn/Article_en/CJFDTOTAL-HGXC2007S1008.htm
FFFC. Unknown. Best Practice Guidance for Use of Class B Firefighting Foams. Available from:
http://www.fffc.org/images/bestpracticeguidance2.pdf
Fluorocouncil. 2014. Guidance for Best Environmental Practices (BEP) for the Global Apparel
Industry – including focus on fluorinated repellent products. Available from:
https://fluorocouncil.com/PDFs/Guidance-for-Best-Environmental-Practices-BEP-for-theGlobal-Apparel-Industry.pdf
Hintzer K, Obermaier E, Schwertfeger W. 2006. Patent: Removal of fluorinated surfactants from
waste water. Patent No. US 7018541 B2
Hintzer K and Schwertfeger W. 2014. Fluoropolymers—Environmental Aspects, in Handbook of
Fluoropolymer Science and Technology (eds D. W. Smith, S. T. Iacono and S. S. Iyer), John Wiley &
Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118850220.ch21
Johnson DW, Teter KS. 2010. Patent: Thermal reduction of fluoroether carboxylic acids or salts from
fluoropolymer dispersions. Patent No. WO 2010129842 A1.
Kuhls J, Weiss E. 1983. Patent: Concentrated dispersions of fluorinated polymers and process for
their preparation. Patent No. US 4369266 A.
Nomura J, Matsuoka Y. 2010. Patent: Method for decomposing water-soluble fluorinated organic
compound. Patent No. US 20100324352 A1.
Obermeier R, Stefaniak G. 1997. Patent: Process for the recuperation of fluorinated carboxylic acids.
Patent No. EP 0632009 B1.
Sulzbach RA, Kowatsch W, Steidl D. 1999. Patent: Recovery of highly fluorinated carboxylic acids
from the gas phase. Patent No. US 5990330 A
Sulzbach RA, Grasberger R, Brandenburg RA. 2001. Patent: Recovery of highly fluorinated
carboxylic acids from the gaseous phase. Patent No. US 6245923 B1
Sun B, Song X, Heng Z, Sui X. 2008. Patent: 聚四氟乙烯分散树脂生产废水中全氟辛酸铵的处理
方法[Method for treating perfluoro ammonium caprylate in waste water for PTFE dispersion resin
production]. Patent No. CN 100420666 C. [in Chinese]
Tang Y, Xu P, Zhou X. 2009. Recovery and application of perfluorooctanoic acid (PFOA). OrganoFluorine Industry 4, 43–7. [in Chinese] Available from:
http://en.cnki.com.cn/Article_en/CJFDTOTAL-YJFG200904013.htm
15
US EPA. 2003. Voluntary Actions to Evaluate and Control Emissions of Ammonium
Perfluorooctanoate (APFO). Letter from Charles D. Allen, Asahi Glass Fluoropolymers USA, Inc.;
Takahiko Sakanoue, Daikin America, Inc.; James E. Gregory, Dyneon LLC.; and Richard J.
Angiullo, E.I. duPont de Nemours & Company, to Stephen L. Johnson, USEPA. March 14, 2003.
Administrative Record 226, No. 1304 (AR226-1304).
Xie X, Bai R, Li J, Chen B. 2009. Promoting PFOA replacement technology, implementing industry
responsibility for environmental protection. Presentation at 7th National Workshop on Market
Development and Applications of Functional Fluorine and Silicon Materials and Coatings, on August
1, 2009 in Guiyang, China [in Chinese; available from:
http://d.g.wanfangdata.com.cn/Conference_7196679.aspx]
Yu K, Song X, Cui L, Han S. 2008. Patent: 分散法聚四氟乙烯树脂生产中全氟辛酸铵的回收处理
方法。[Method for recovering and treating perfluoro ammonium caprylate for PTFE resin
production by dispersion method.] Patent No. CN 100376537 C. [in Chinese]
16
V. Additional information on alternatives to PFOA in fluoropolymer production
1. Daikin has developed its own fluorinated PFOA replacement with the molecular formula:
CF3OCF(CF3)CF2OCF(CF3)COO-NH4+ (Hintzer and Schwertfeger, 2014).
2. Several major Chinese fluoropolymer producers have also developed alternative substances to
replace PFOA in their fluoropolymer (or fluoroelastomer) production processes. These possible
alternative substances remain to be PFASs and can be divided into two sub-groups: (1) shorterchain homologues of PFOA-related compounds (e.g., 6:2 fluorotelomer carboxylic acid or 6:2
FTCA (Xu et al., 2011) and PBSF-based substances (Lu et al., 2011)), and (2) perfluoroetherbased alkyl acids (PFEAAs; Lu et al., 2011; Wang et al., 2010; Xie et al., 2010; Zhang et al.,
2012). Examples of such perfluoroether-based alkyl acids include, but are not limited to,
CF3O(CF2CF(CF3)O)(CF2OO)(C(CF3)FO)COO- (Xie et al., 2010; Zhang et al., 2012) and
CF3CF2(CF2OCF(CF3))n-1COO- (Wang et al., 2010).
3. The current progress of replacing PFOA by Chinese fluoropolymer and fluoroelastomer producers
remains unclear, except that Zhonghao Chenguang reported to have selected and industrialized a
perfluoroether-based alkyl acid-based alternative to PFOA for its production processes of PTFE and
fluoroelastomers since 2007 (Xie et al., 2009).
4. Furthermore, various fluoropolymer manufacturers are exploring and have patented a number of
fluorinated emulsifier-free aqueous emulsion polymerization processes (Hintzer and Schwertfeger,
2014). These include: (1) emulsifier-free polymerization of amorphous standard co/terpolymers
comprising TFE, HFP and VDF; (2) development of non-fluorinated emulsifiers for VDF-containing
polymers such as polyvinyl/acrylic acids, derivatives of polyethylene/propylene glycols,
alkylphosphate esters, vinyl acids, siloxanes, silanes, long-chain hydrocarbon acids, and derivatives
of sugars; and (3) development of so-called “surfmers” (which are surfactants that can also act as
monomers in the polymerization action) for specific classes of fluoropolymers.
5. Moreover, Hintzer and Schwertfeger from 3M/Dyneon GmbH conclude that “the changing landscape
with regard to regulation of APFO and related fluorosurfactants have led fluoropolymer
manufacturers to re-evaluate and in some cases introduce polymerization approaches, which in
previous times were considered not economically feasible” (Hintzer and Schwertfeger, 2014).
6. References
Hintzer K and Schwertfeger W. (2014) Fluoropolymers—Environmental Aspects, in Handbook of
Fluoropolymer Science and Technology (eds D. W. Smith, S. T. Iacono and S. S. Iyer), John Wiley &
Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118850220.ch21
Lu W, Zhang B, Zhu Y, Gu W. 2011. Study on the PFOA Substitute and its Application in the
Polymerization of Fluoroelastomer. Organo – Fluorine Industry 2, 20-23. Available from:
http://cnki.caas.cn/KCMS/detail/detailall.aspx?filename=yjfg201102005&dbcode=CJFQ&dbname=
CJFD2011
Wang H, Fang J, Li W, Li X, Hao H. 2010. Patent: Fluorine-containing emulsifier for fluoropolymer
emulsion polymerization and preparation thereof. Patent No. CN 101745338 B.
Xie X, Bai R, Li J, Chen B. 2009. Promoting PFOA replacement technology, implementing industry
responsibility for environmental protection. Presentation at 7th National Workshop on Market
Development and Applications of Functional Fluorine and Silicon Materials and Coatings, on August
1, 2009 in Guiyang, China [in Chinese; available from:
http://d.g.wanfangdata.com.cn/Conference_7196679.aspx]
Xie X, Qu J, Bai R, Zhang J, Yang X. 2010. Patent: Peroxidic fluoropolyether and its use in emulsion
polymerization of fluorin-containing monomer. Patent No. WO 2010017665 A1.
17
Xu Y, Zhao M, Li H, Lu W, Su X, Han Z. 2011. A novel fluorocarbon surfactant: synthesis and
application in emulsion polymerization of perfluoroalkyl methacrylates. Paint & Coatings Industry
41,17–21. [in Chinese] Available from: http://en.cnki.com.cn/Article_en/CJFDTOTALTLGY201108006.htm
Zhang J, Hu X, He J, Bai R. 2012. Patent: Preparation method and use for fluorine-containing
microemulsion. Patent No. WO 2012058793 A1
18
VI. Existing regulatory measures in China
1. In 2011, PFOA-relevant technology and products were added to the Catalogue for the Guidance
of Industrial Structure Adjustment in China (NDRC, 2013), including that new installation of
PFOA production facilities should be restricted, that PFOA-containing paints and
fluoropolymers that use PFOA in the polymerization should be eliminated, and that development
of alternatives to PFOA should be encouraged.
2. In 2013, fluoropolymer coatings for non-stick pans, kitchenware and food processing equipment
that use PFOA in the polymerisation were recognized as products with high pollution and high
environmental risk (“dual-high” products) in the Comprehensive Catalog for Environmental
Protection (China MEP, 2015).
3. In 2016, China MEP published a new technical requirement for textile products (China MEP,
2015), which came into force in January 2017. In particular, the new technical requirement sets
the limits of PFOA levels to be 0.05 mg/kg in coated infants textile products and 0.1 mg/kg in all
other coated textile products, respectively.
4. References
NDRC 2013. 产业结构调整指导目录 (2011年本) (修正). [Catalogue for the Guidance of
Industrial Structure Adjustment (2011) (revised)]. Available from:
http://www.gov.cn/gongbao/content/2013/content_2404709.htm
China MEP 2015. 高污染、高环境风险产品名录 (2015 年版). [Comprehensive Catalogue for
Environmental Protection. (2015)] Available from:
http://www.mep.gov.cn/gkml/hbb/bgth/201512/W020151231390609524367.pdf
China MEP 2016. 中华人民共和国国家环境保护标准 – 环境标志产品技术要求 纺织产品
(HJ 2546-2016). [People’s Republic of China National Environmental Protection Standards Technical requirement for environmental labeling products. Textile Products (HJ 2546-2016)]
Available from:
http://kjs.mep.gov.cn/hjbhbz/bzwb/other/hjbz/201612/W020161202321802029261.pdf
19