1 Can a smog chamber be used to explain why polar bears have 8.6 ng/g of perfluoro octanoic acid in...

1

Can a smog chamber be used to explain why polar bears have 8.6 ng/g of perfluoro

octanoic acid in their body?

Ole John NielsenDepartment of ChemistryUniversity of Copenhagen

www.cogci.dk

http://www.cogci.dk/

2

Acknowledgements

Mads P. S. AndersenJPL-NASA, Pasadena, CA, USA

Tim. J. Wallington, Mike. P. Hurley, Jim. C. BallFord Motor Company, Dearborn, MI, USA

Scott. A. MaburyUniversity of Toronto, Toronto, ON, Canada

3

Why am I here?

4

Outline

1. Who am I?2. Why the interest in PerFluoro Organic Acids

(PFOAs) and FluoroTelomer alcohols (FTOHs)?3. What are PFOA, PFCA and PFOA again?

4. Use of FTOH = CnF2n+1CH2CH2OH (straight chain)5. Atmospheric chemistry of FTOHs6. Environmental Impacts and Conclusions7. Discussions

5

Who am I?1954 Born1973 Began at UoC (chemistry and physics)1974 Important Atmospheric Year1978 M.Sc. and on to do a PhD at Risø Nat. Lab.1978-95 Risø National Laboratory1995-96 Ford Research Center Aachen, Germany1996-99 Risø National Laboratory1999-? Professor at UoC2007 Nobel Peace Prize together with Al Gore and 2500 scientists

Gas phase kinetics and reaction mechanisms - relevant to the atmosphere – How? Why?

IPCC – Intergovernmental Panel of Climate Change

6

2. Why the interest in PerFluoro Organic Acids (PFOAs) and FluoroTelomer alcohols (FTOHs)?

• What do you think?• The interest in environmental chemistry is driven by?• Health Concerns

7

Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers

Contact Us | Print Version

January 12, 2005: Draft PFOA Risk Assessment submitted to EPA Science Advisory Board for Peer Review: SAB meeting February 22-23, 2005.

PFOA stands for perfluorooctanoic acid, a synthetic (man-made) chemical that does not occur naturally in the environment. PFOA is sometimes called "C8." Companies use PFOA to make fluoropolymers, substances with special properties that have thousands of important manufacturing and industrial applications. Consumer products made with fluoropolymers include non-stick cookware and breathable, all-weather clothing. More BASIC INFORMATION about PFOA.

EPA began its investigation because PFOA is very persistent in the environment, was being found at very low levels both in the environment and in the blood of the general U.S. population, and caused developmental and other adverse effects in laboratory animals. EPA summarized its concerns and identified data gaps and uncertainties about PFOA in a notice published in the Federal Register.

http://www.epa.gov/opptintr/pfoa/contact.htm

http://www.epa.gov/cgi-bin/epaprintonly.cgi

http://www.epa.gov/opptintr/pfoa/pfoarisk.htm

http://www.epa.gov/opptintr/pfoa/pfoainfo.htm

http://www.epa.gov/opptintr/pfoa/pfoafr.htm

http://www.epa.gov/

8

Risk AssessmentYou will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.In January 2005, the EPA Office of Pollution Prevention and Toxics submitted a Draft Risk Assessment of the Potential Human Health Effects Associated With Exposure to Perfluorooctanoic Acid and Its Salts (PFOA) (PDF) (132pp, 450KB) to the EPA Science Advisory Board (SAB) for formal peer review. EPA sought this early stage scientific peer review from an outside panel of experts in order to ensure the most rigorous science is used in the Agency's ongoing evaluation of PFOA. That draft was preliminary and did not provide conclusions regarding potential levels of concern. The SAB reviewed the information that was available at the time, and suggested that the PFOA cancer data are consistent with the EPA Guidelines for Carcinogen Risk Assessment descriptor "likely to be carcinogenic to humans." Since its review, additional research has been conducted pertaining to the carcinogenicity of PFOA. EPA is still in the process of evaluating this information and has not made any definitive conclusions regarding potential risks, including cancer, at this time.

More information can be found on the SAB PFOA Review Panel Website.

EPA is not waiting for all of the answers to be known before taking action, however. In January 2006, EPA asked eight companies in the industry to commit to reducing PFOA from facility emissions and product content by 95 percent no later than 2010, and to work toward eliminating PFOA from emissions and product content no later than 2015. All eight of the invited companies submitted commitments to the Stewardship Program by March 1, 2006. Read more information on the PFOA 2010/15 Stewardship Program.

http://www.epa.gov/epahome/pdf.html

http://www.epa.gov/opptintr/pfoa/pubs/pfoarisk.pdf




http://yosemite.epa.gov/sab/sabpeople.nsf/WebCommittees/BOARD

http://cfpub.epa.gov/ncea/raf/recordisplay.cfm?deid=116283

http://www.epa.gov/sab/panels/pfoa_rev_panel.htm

http://www.epa.gov/opptintr/pfoa/pubs/stewardship/index.html

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In 2006, former Administrator Stephen L. Johnson invited the eight major fluoropolymer and telomer manufacturers to join in a global stewardship program with two goals:To commit to achieve, no later than 2010, a 95% reduction, measured from a year 2000 baseline, in both facility emissions to all media of PFOA, precursor chemicals that can break down to PFOA, and related higher homologue chemicals, and product content levels of these chemicals.To commit to working toward the elimination of these chemicals from emissions and products by 2015.

Participating companies include: Arkema, Asahi, Ciba, Clariant, Daikin, 3M, DuPont, Solvay Solexis

Submitted baseline year 2000 data on emissions and product content at the end of October 2006.

Report annual progress toward goals each succeeding October and report progress in terms of both U.S. and global operations.

Companies also agreed to work cooperatively with EPA and establish scientifically credible analytical standards and laboratory methods to ensure comparability of reporting

10

Long chain perfluorinated acids (PFCAs/PFAs) observed in fauna in urban and remote locations

PFOA (perfluorooctanoic acid) C7F15C(O)OH

PFNA (perfluorononanoic acid) C8F17C(O)OH

PFDA (perfluorodecanoic acid) C9F19C(O)OH

PFUA (perfluoroundecanoic acid) C10F21C(O)OH

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CC

FF

FF

FF

FF

FF

FF

PFPeA

OHO

F

F

3. What are PFOAs, PFCAs and PFOA?PerFluorinated Organic AcidsPerFluorinated Carboxylic AcidsPerFluorinated Octanoic Acid

12

In the far north... …in Polar Bears?

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CC

FF

FF

FF

FF

FF

FF

PFPeA

OHO

F

FPFACs ng/gPFOA (8) 8.6PFNA (9) 180PFDA (10) 56PFUNA (11) 63 PFDoA (12) 6.2 PFTrA (13) 11PFTA (14) 0.51PFPeA (15) <0.5

Martin et al., EST 38 (2004) 373.

13

Facts:

No natural sources. Water-soluble PFCA salts used in fluoropolymer processing. Not released in major quantities. Presence of PFCAs in remote areas suggests atmospheric source.

The science (why) question?

Why are they here?

Where do long chain Perfluorocarboxylicacids

(PFCAs), CnF2n+1COOH come from?

Our hypothesis:

They are atmospheric degradation products from other long chain fluorinated compounds emitted to the atmosphere

14

22,000 liters of AFFF; ~300 kg of PFOS!

“Airport Foam Seeps into Creek”Toronto Star, June 10, 2000

15

Etobicoke Creek Fish Liver Samples; Jan 5, 2001 (spill + 7 months)

10.00 10.50 11.00 11.50 12.00 12.50 13.00 13.50 14.00Time0

100

%

0

100

%

0

100

%

0

100

%

0

100

%

0

100

%

0

100

%

0

100

%

JAN17-ETOBCREEK-DOWNSTREAM MRM of 12 Channels ES- 713 > 669

1.46e3


4.46e3


1.82e3


3.03e3


2.52e5


1.06e3


2.18e3


1.06e3

PFOS

PFDoA

PFUnA

PFDA

PFOA

PFHxS

PFHpA

PFTA

C12

C14

C10

C8

C7

C11

C8S

C6S

Moody, C.A., W.C. Kwan, J.W. Martin, D.C.G. Muir, and S.A. Mabury. 2001. Determination of Perfluorinated Surfactants in Surface Water Samples by Two Independent Analytical Techniques – Liquid Chromatography/Tandem Mass Spectrometry and 19F NMR. Analytical Chemistry. 73:2200-2206.

Moody, C.A., J. W. Martin, W. C. Kwan, D. C. G. Muir, and S. A. Mabury. 2002. Monitoring Perfluorinated Surfactants in Biota and Surface Water Samples Following an Accidental Fire-Fighting Foam Release into Etobicoke Creek. Environ. Sci. Technol. 36:545-551.

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CHO

O

FF

FF

FF

FF

FF

FF

16

4. FTOH = fluorotelomer alcohol

2001 – FTOHs observed in atmosphere. Oxidation of FTOHs could be a source of PFCA

source (against conventional wisdom in atmospheric chemistry community).

CnF2n+1CH2CH2OH (straight chain)

4:2 FTOH = C4F9CH2CH2OH




17

PolyfluoroAlcohols are highly volatile!!!

5504503502501505050.01

.1

1

10

100

1000

10000

Molecular Mass

Log

P (

Pasc

als

)

Hydrocarbon Alcohols

Fluorotelomer Alcohols

HC data from Daubert & Danner; FTOH data from Lei et al, submitted J Chem Eng Data and Stock et al, ES&T in press.

FF

FFF

F

FFF

F

FF

F

C

FF

COH

F

F H

H

H

H

8:2 FTOH = 212 Pa

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FTOH based coatings heavily used in consumer products;

*TRP Presentation toUSEPA OPPT. Nov 25, 2002US Public Docket AR226-1141

5x106 kg/yr40% in North America80% are in polymers*

Carpet Treatment

Polymer

Potential Sources?

Degradation

N C

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CH2

H2COH

F

F

F F

F F

F F

F F

F F

F F

F

FF

C

F FC

OHH H

H H

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CH2

H2C

F

F

OO

OO

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

CH2

H2C

F

F

O

F

F

F

F

F

F

F

F

F

F

F

F

F

FF

Urethane EtherEster

CH2

H2C

F

F

Residual

19

Three necessary conditions:

(1) FTOH survive atmospheric transport

(2) FTOH degrade to give PFCAs

(3) Magnitude of PFCA formation must be significant

Use a FTIR Smog chamber

Research Question:

Does atmospheric oxidation of FTOHs contribute significantly to PFCA burden in remote locations?

20

4. Experimental apparatus and setup

21

FTIR SMOG CHAMBERFTIR SMOG CHAMBER

o 140 L Pyrex chamber

o X/Cl2/N2/O2/black-lamps

o X/CH3ONO/NO/air/black-lamps

296 K, 700 Torr

25


(1) Do FTOHs survive atmospheric transport?

Measurement of k(OH+FTOH) – Why?

(2) Do FTOHs degrade to give PFCAs?

(3) Magnitude of PFCA formation must be significant?


26

UV irradiation of

FTOH/reference/CH3ONO/NO/air mixtures

FTOH = 4:2 FTOH, 6:2 FTOH, or 8:2 FTOH

reference = C2H2 or C2H4

CH3ONO CH3O + NO

CH3O + O2 HCHO + HO2

HO2 + NO OH + NO2

OH + FTOH products (1)

OH + reference products (2)

27

OH + FTOH products (1)

OH + reference products (2)

][reference[OH]k]reference[

]FTOH[]OH[k]FTOH[

ss2ss1

dt

d

dt

d

Integration gives:

t[OH]k]reference[

]reference[t[OH]k

]FTOH[

]FTOH[ss2ss1

t

toLn

t

toLn

FTOH and reference have equal exposure to OH radicals, hence:

t

to

2

1

t

to

][reference

][reference

k

k

[FTOH]

[FTOH]LnLn

28

Loss of FTOH (squares = 4:2; circles = 6:2; triangles = 8:2) versus C2H2

and C2H4 on exposure to OH radicals in 700 Torr of air diluent at 296 K.

Ln ([Reference]to/[Reference]t)0.0 0.5 1.0 1.5

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Ln([

F(C

F2C

F2)

n(C

H2)

2OH

] to/[F

(CF

2CF

2)n(

CH

2)2O

H] t)

C2H2

C2H4

No discernable difference in reactivity of OH radicals towards 4:2, 6:2, and 8:2 FTOH

29

OH + CnF2n+1CH2CH2OH → products (10)

OH + C2H2 → products (11)

OH + C2H4 → products (12)

Linear fits give k10/k11 = 1.18±0.15 and k10/k12 = 0.131±0.018.

Using k11 = 8.5 x 10-13 and k12 = 8.66 x 10-12 gives

k10 = (1.00±0.13) x 10-12 and (1.13±0.16) x 10-12 cm3 molecule-1 s-1.

Final value, k10 = (1.07±0.22) x 10-12 cm3 molecule-1 s-1.

Ln ([Reference]to/[Reference]t)0.0 0.5 1.0 1.5

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Ln([

F(C

F2C

F2) n

(CH

2) 2

OH

] to/[F

(CF

2C

F2) n

(CH

2) 2

OH

] t)

C2H2

C2H4

30

Assuming:

atmospheric lifetime* for CH3CCl3 = 5.7 years

k(CH3CCl3 + OH) = 1.0 x 10-14 cm3 molecule-1 s-1

then

atmospheric lifetime* of F(CF2)nCH2CH2OH

(1.0x10-14)/(1.1x10-12) x 5.7 x 365 20 days.

* with respect to reaction with OH radicals

FTOH Lifetime Estimate

31

Other loss mechanisms?

Photolysis – should be negligible

Rainout – estimated to be negligible

Dry deposition – lifetime estimated to be 8 years

Homogeneous reactions other than with OH - unlikely

Atmospheric lifetime determined by reaction with OH and is approximately 20 days.

32

Ramifications of Lifetime

(1) Estimate flux of 100-1000 t yr-1 necessary to sustain observed atmospheric concentration.

(2) FTOH have negligible GWP

(3) Spatial distribution will be inhomogeneous

(4) FTOH will be transported to remote locations. Global average wind speed = 5 m s-1, 20 days = 8500 km.

33

Assuming 5m/s winds and a 20d lifetime, FTOHs could be transported over 8500 km

20 days… Long Enough for Long Range Transport?

Copenhagen to Detroit = 6500 km

34



YES




35

0.00

0.05

0.10

0.15

0.20

0.25

IR A

bso

rban

ce

0.00

0.05

0.10

0.15

0.20

0.25

0.00

0.02

0.04

0.06

0.08

Wavenumber (cm-1)

700 900 1100 1300 1500 1700 1900

0.00

0.05

0.10

0.15

(A) before irradiation

(B) 10 sec irradiation

(C) Product

(D) CF3(CF2)3CH2CHO

FTIR study of 4:2 FTOH oxidation

CF3(CF2)3CH2CHO

is the major primary

product from Cl

atom and OH

radical initiated

oxidation of 4:2 FTOH

36

FTOH Oxidation mechanism

CnF2n+1CH2CH2OH + OH CnF2n+1CH2C(•)HOH + H2O

CnF2n+1CH2C(•)HOH + O2 CnF2n+1CH2CHO + HO2

37

[CF3(CF2)3CH2CH2OH] / [CF3(CF2)3CH2CH2OH]0

0.0 0.2 0.4 0.6 0.8 1.0

[CF

3(C

F2) 3

CH

2C

HO

] /

[CF

3(C

F2) 3

CH

2C

H2O

H] 0

0.0

0.1

0.2

0.3

0.4

0.5

CnF2n+1CH2CHO is

reactive …

Gives secondary products …

38

[CF3(CF2)3CH2CHO] / [CF3(CF2)3CH2CH2OH]0

0.0 0.2 0.4 0.6 0.8 1.0

[pro

du

cts]

/ [C

F3(C

F2) 3

CH

2C

H2O

H] 0

0.0

0.1

0.2

0.3

0.4

0.5

[UN

KN

OW

N]

/ [C

F3(C

F2) 3

CH

2C

H2O

H] 0

0.00

0.05

0.10

0.15

0.20

0.25

CF3(CF2)3CHO

CF3(CF2)3CH2COOH

UNKNOWN

Secondary products:

CF3(CF2)3CHO,

CF3(CF2)3CH2COOH,

CF3(CF2)3C(O)OOH

39

FTOH Oxidation mechanism

CnF2n+1CH2CH2OH + OH CnF2n+1CH2C(•)HOH + H2O

CnF2n+1CH2C(•)HOH + O2 CnF2n+1CH2CHO + HO2

CnF2n+1CH2CHO + OH + O2 CnF2n+1CH2C(O)OO + H2O

CnF2n+1CH2C(O)OO + NO CnF2n+1CH2C(O)O + NO2

CnF2n+1CH2C(O)O CnF2n+1CH2 + CO2

CnF2n+1CH2 + O2 CnF2n+1CH2O2

CnF2n+1CH2O2 + NO CnF2n+1CH2O + NO2

CnF2n+1CH2O + O2 CnF2n+1CHO + HO2

40

[CF3(CF2)3CH2CHO] / [CF3(CF2)3CH2CH2OH]0

0.0 0.2 0.4 0.6 0.8 1.0

[pro

du

cts]

/ [C

F3(C

F2) 3

CH

2C

H2O

H] 0

0.0

0.1

0.2

0.3

0.4

0.5

[UN

KN

OW

N]

/ [C

F3(C

F2) 3

CH

2C

H2O

H] 0

0.00

0.05

0.10

0.15

0.20

0.25

CF3(CF2)3CHO

CF3(CF2)3CH2COOH

UNKNOWN

Secondary products:

C4F 9CHO,

C4F9CH2COOH

C4F9C(O)OOH

Secondary products are reactive …

41

0.00

0.02

0.04

0.06

0.08

0.00

0.10

0.20

0.30

0.40

0.50

0.60

IR A

bso

rba

nc

e

0.00

0.20

0.40

0.60

0.80

Wavenumber (cm-1)

1400 1600 1800 3500

0.00

0.10

0.20

0.30

(A) before irradiation

(B) 8.5 minutes irradiation

(C) residual

(D) CF3(CF2)3COOH

Tertiary products include:

COF2, CF3OH

C4F9COOH

Conclusion of FTIR experiments:

simulated atmospheric

oxidation of 4:2 FTOH (in absence

of NOx) gives a small (few %) yield

of C4F9COOH

42

in presence of NOx

4:2 FTOH C4F9CHO C4F9COOH

FTIR data shows that in gas phase:

in absence of NOx

4:2 FTOH C4F9CHO C4F9COOH

Likely explanation, presence of HO2 radicals in absence of NOx

Well established that CH3C(O)O2 + HO2 gives acetic acid and peracetic acid, ,presumably CxF2x+1C(O)O2 + HO2 reaction gives

CxF2x+1COOH and CxF2x+1COOOH.

Product study of CxF2x+1C(O)O2 + HO2 (x=1-4) to test this idea.

43

CnF2n+1C(O)O2 and HO2 radicals generated by UV irradiation of CnF2n+1CHO/H2/Cl2 mixtures in 100-700 Torr of air at 296±2 K:

Cl2 + h 2Cl

Cl + CnF2n+1CHO CnF2n+1CO + HCl

CnF2n+1CO + O2 + M CnF2n+1C(O)O2 + M

Cl + H2 H + HCl

H + O2 + M HO2 + M

CnF2n+1C(O)O2 + HO2 products

CnF2n+1C(O)O2 + CnF2n+2C(O)O2 products

As [H2]o/CnF2n+1CHO]o , products/products ,

Method

44

IR spectra obtained before (A) and after

(B) 55 s of irradiation of a mixture of 18.8 mTorr C2F5C(O)H,

218 mTorr Cl2 and

2.8 Torr H2 in 700

Torr of air. The consumption of

C2F5C(O)H was 63%.

45

PFCAs are products of

CxF2x+1C(O)O2 + HO2 reaction

Offers reasonable

explanation of observed PFCA formation in 4:2

FTOH expts.

46

Branching ratios in reactions of RC(O)O2 with HO2 radicals under ambient conditions (700-760 Torr, 2962K).

RC(O)O2 Products Reference

RC(O)OOH+O2 RC(O)OH+O

3

RC(O)O+O2+OH

CH3C(O)O2 0.40 0.16 0.20 0.08 0.40 0.16 [21]

CF3C(O)O2 0.09 0.04 0.38 0.04 0.56 0.05 This work

C2F5C(O)O2 < 0.06 0.24 0.04 0.76 0.04 [27]

C3F7C(O)O2 < 0.03 0.10 0.02 0.90 This work

C4F9C(O)O2 < 0.03 0.08 0.02 0.90 This work

47

CF2

CF3

O

OO HO2+

CF2

CF3

O

OO

OO

H

CF2

CF3

O

OO

O

OH

C2F5C(O)OH + O3

CF2

CF3

O

OO

OO

H

C2F5C(O)OOH + O 2

CF2

CF3

O

OO

OO

H

C2F5C(O)O + O2 + OH

a b c

49



YES


YES



50

FTOH flux into Northern Hemisphere = 100-1000 t yr-1

Assume molar PFCA yield from FTOH of 1-10%

Hence, PFCA flux = 1-100 t yr-1

Assume even spatial distribution

Hence, PFCA flux to Arctic = 0.1 - 10 t yr-1

Persistent organochlorine pesticides arctic loading =1.8 t yr-1

Organochlorine pesticides detectable in polar bears at a similar concentration to PFCAs ( 100-1000 ng/g)

Order of magnitude calculations suggest atmospheric oxidation of FTOHs is plausible explanation of PFCAs in

remote areas.

51



YES


YES


Looks plausible … more work …


53

Concentration of PFOA (in molecule cm-3) at 50 m. altitude in the University of Michigan 3D model (IMPACT) for January and July. The color scale extends from (A) 0 to 1.2x103 and (B) 0 to 3x103 molecule cm-3.

UIUC 2D model

55

Conclusions

1. The available evidence suggests, that the atmospheric oxidation of FTOHs makes a significant contribution to the PFCA burden in remote locations.

2. This is just the tip of the ice berg

3. The automobile industry uses large quantities of fluoropolymers but little, if any, FTOHs. Vehicles do not appear to be a source of PFCAs

56

The ”smog” quartet

57

The Atmospheric Science Group

Ch

F

Dk

FinDk Dk

Dk

Dk

Dk

Dk

Dk

RusD

Est

Est

US

58

Extra slides

60


PFNA = C8F17C(O)OH

PFOA = C7F15C(O)OH


(1) FTOH survive atmospheric transport

(2) FTOH degrade to give PFCAs


Use a FTIR Smog chamber

Research Question:


1 Can a smog chamber be used to explain why polar bears have 8.6 ng/g of perfluoro octanoic acid in...

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