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Ole John Nielsen Department of Chemistry University of Copenhagen cogci.dk

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 Nielsen Department of Chemistry University of Copenhagen www.cogci.dk. Acknowledgements. Mads P. S. Andersen JPL-NASA, Pasadena, CA, USA

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Ole John Nielsen Department of Chemistry University of Copenhagen cogci.dk

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  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 Nielsen Department of Chemistry University of Copenhagen www.cogci.dk

  2. Acknowledgements Mads P. S. Andersen JPL-NASA, Pasadena, CA, USA Tim. J. Wallington, Mike. P. Hurley, Jim. C. Ball Ford Motor Company, Dearborn, MI, USA Scott. A. Mabury University of Toronto, Toronto, ON, Canada

  3. Why am I here?

  4. Outline • Who am I? • Why the interest in PerFluoro Organic Acids (PFOAs) and FluoroTelomer alcohols (FTOHs)? • What are PFOA, PFCA and PFOA again? • Use of FTOH = CnF2n+1CH2CH2OH (straight chain) • Atmospheric chemistry of FTOHs • Environmental Impacts and Conclusions • Discussions

  5. Who am I? 1954 Born 1973 Began at UoC (chemistry and physics) 1974 Important Atmospheric Year 1978 M.Sc. and on to do a PhD at Risø Nat. Lab. 1978-95 Risø National Laboratory 1995-96 Ford Research Center Aachen, Germany 1996-99 Risø National Laboratory 1999-? Professor at UoC 2007 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. Contact Us | Print Version Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers

  8. Risk Assessment You 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. 

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

  11. In the far north... …in Polar Bears? PFACs ng/g PFOA (8) 8.6 PFNA (9) 180 PFDA (10) 56 PFUNA (11) 63 PFDoA (12) 6.2 PFTrA (13) 11 PFTA (14) 0.51 PFPeA (15) <0.5 Martin et al., EST 38 (2004) 373.

  12. 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

  13. “Airport Foam Seeps into Creek”Toronto Star, June 10, 2000 22,000 liters of AFFF; ~300 kg of PFOS!

  14. Etobicoke Creek Fish Liver Samples; Jan 5, 2001 (spill + 7 months) PFTA C14 PFDoA C12 PFUnA C11 PFDA C10 PFOS C8S PFOA C8 PFHxS C6S PFHpA C7 • 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.

  15. 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 6:2 FTOH = C6F13CH2CH2OH 8:2 FTOH = C8F17CH2CH2OH 10:2 FTOH = C10F21CH2CH2OH

  16. PolyfluoroAlcohols are highly volatile!!! 8:2 FTOH = 212 Pa HC data from Daubert & Danner; FTOH data from Lei et al, submitted J Chem Eng Data and Stock et al, ES&T in press.

  17. FTOH based coatings heavily used in consumer products; 5x106 kg/yr 40% in North America 80% are in polymers* *TRP Presentation to USEPA OPPT. Nov 25, 2002 US Public Docket AR226-1141

  18. Research Question: Does atmospheric oxidation of FTOHs contribute significantly to PFCA burden in remote locations? • Three necessary conditions: • FTOH survive atmospheric transport • FTOH degrade to give PFCAs • Magnitude of PFCA formation must be significant Use a FTIR Smog chamber

  19. 4. Experimental apparatus and setup

  20. 140 L Pyrex chamber X/Cl2/N2/O2/black-lamps X/CH3ONO/NO/air/black-lamps FTIR SMOG CHAMBER 296 K, 700 Torr

  21. Does atmospheric oxidation of FTOHs contribute significantly to PFCA burden in remote locations? • Three necessary conditions: • 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?

  22. 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)

  23. OH + FTOH  products (1) OH + reference  products (2) Integration gives: FTOH and reference have equal exposure to OH radicals, hence:

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

  25. 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.

  26. FTOH Lifetime Estimate 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

  27. 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.

  28. Ramifications of Lifetime • Estimate flux of 100-1000 t yr-1 necessary to sustain observed atmospheric concentration. • FTOH have negligible GWP • Spatial distribution will be inhomogeneous • FTOH will be transported to remote locations. Global average wind speed = 5 m s-1, 20 days = 8500 km.

  29. 20 days… Long Enough for Long Range Transport? Assuming 5m/s winds and a 20d lifetime, FTOHs could be transported over 8500 km Copenhagen to Detroit = 6500 km

  30. Does atmospheric oxidation of FTOHs contribute significantly to PFCA burden in remote locations? Three necessary conditions: (1) Do FTOHs survive atmospheric transport? YES (2) Do FTOHs degrade to give PFCAs? (3) Magnitude of PFCA formation must be significant

  31. 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

  32. FTOH Oxidation mechanism CnF2n+1CH2CH2OH + OH  CnF2n+1CH2C(•)HOH + H2O CnF2n+1CH2C(•)HOH + O2 CnF2n+1CH2CHO + HO2

  33. CnF2n+1CH2CHOis reactive … Gives secondary products …

  34. Secondary products: CF3(CF2)3CHO, CF3(CF2)3CH2COOH, CF3(CF2)3C(O)OOH

  35. 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

  36. Secondary products: C4F 9CHO, C4F9CH2COOH C4F9C(O)OOH Secondary products are reactive …

  37. 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

  38. FTIR data shows that in gas phase: in absence of NOx 4:2 FTOH   C4F9CHO C4F9COOH in presence 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.

  39. Method 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 ,

  40. 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%.

  41. PFCAs are products ofCxF2x+1C(O)O2 + HO2 reaction Offers reasonable explanation of observed PFCA formation in 4:2 FTOH expts.

  42. Branching ratios in reactions of RC(O)O2 with HO2 radicals under ambient conditions (700-760 Torr, 2962K).

  43. Does atmospheric oxidation of FTOHs contribute significantly to PFCA burden in remote locations? Three necessary conditions: (1) Do FTOHs survive atmospheric transport? YES (2) Do FTOHs degrade to give PFCAs? YES (3) Magnitude of PFCA formation must be significant

  44. 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.

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