Document zdwOE4XOmZzJvLvrQnvdnE7en
AR RR6 _ 3664
PFCAs and Precursors
Simplified Terminology/Sources/Fate
Consultation Meeting on PFCA Action Plan February 2006
000092
Purpose
> Intended to provide terminology and simplified background on PFCA sources and environmental fate.
> Useful in discussing the proposed Action Plan.
000093
Presentation Outline
> Perfluorinated Carboxylic Acids > Fluorotelomer Intermediates > Fluorotelomer Based Substances > "Residuals" > Pathways to PFCAs
Via Residuals Via degradation of Fluorotelomer Based
Substances
3 000094
Perfluorinated Carboxylic Acids (PFCAs)
> General structure:
> Can be referred to by the number of carbons in the molecule; e.g.. Perfluorooctanoic acid called "C8"
> Perfluorodecanoic acid called "C IO "
O 0
4 000095
PFCAs (continued)
> Some PFCAs, notably C8 and C9 are manufactured for industrial use > Estimated total industrial annual production of;
C8 (1999) of -260,000 kg, and
. C9 (2004) of 15,000 to 75,000 kg (Prevedouros et al. 2005)
. Total -300,000 kg/year globally
> Used mainly as a processing aid in the manufacture of fluoropolymers. This action plan does NOT address fluoropolymers e.g. PTFE
n
> C8 is subject to a separate assessment under CEPA (1999) and is not the focus of this proposed action plan
5 000096
Fluorotelomer Intermediates
Used as building blocks in more complex molecules > Fluorotelomer alcohols (FTOHs)
> Fluorotelomer epoxides
cf2.
h2 a
'C
f2 n
.OH
C
H2
> Fluorotelomer olefins
f2 H
-C . ,C
XT % CH;
F2 n
> Note that manufacture of these substances typically produces a range of
carbon chain lengths
> -12,000,000 kg/year produced globally (DuPont: EPAAR 226-1914)
6 000097
Fluorotelomer Based Substances
> Applications include oil/water repellents for textiles, paper and leather, levelling agents In paints and coatings
> 80% of fluorotelomer intermediates used to produce polymeric materials (t r p : e p a a r 226-h 41)
> 20% used to produce chemical
S U b S ta n C e S (TRP: EPAAR226-1141)
3F
R
7 000098
"Residuals"
> Fluorotelomer based substances can contain unreacted or "residual" fluorotelomer intermediates
> ~2 wt% in final substances (Prevedouros et al. 2005) represents a mass of -240,000 kg/year globally of fluorotelomer intermediates
> Little uncertainty associated to this source
8 000099
"Residuals" Conversion to PFCAs
Residual Fluorotelomer Intermediate
> Volatile residuals can escape from commercial substances and are capable of dispersion through the atmosphere (long range transport or LRT), a portion converted to PFCAs and deposited to the earth via precipitation.
> Dispersion via other pathways, e.g. release to sewage treatment through household wastes, and biodegraded to form PFCAs.
> Substances which chemically convert to PFCAs referred to as
"precursors"
9
oooioo
PFCAs from Fluorotelomer Based Substances
Fluorotelomer Based --Fluorotelomer -- PFCA
Substance
Intermediate
> 98% of fluorotelomer intermediates reacted into other substances
> a potential latent source of ~11.8 million kg/year globally
> bonds susceptible to degrade, releasing fluorotelomer intermediates available to convert to PFCAs
10
OOOlOi
PFCAs from Fluorotelomer Based Substances: Research
> Uncertainties
Conditions under which degradation occurs Rates Relative contribution to environmental levels
> Recent EPA settlement with a company compels $5 million to study this issue
> US EPA conducting independent research > Industry studies underway > Academic interest
11 000102
Illustration: Volatilization of Residuals and Liberation of Intermediates
