Lessons Learned from PFAS in Groundwater
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The document discusses patterns of PFAS (per- and polyfluoroalkyl substances) distribution in groundwater related to AFFF (aqueous film-forming foam) use, drawing from a large database of over 2000 sampling locations including airports and fire training centers. It emphasizes findings such as the prevalence of specific PFAS compounds, the complexity of matching PFAS sources, and the need for further research into the fate and transport of these substances. Key takeaways include the importance of calibrating to known source types and understanding the varying formulations and properties of PFAS in different contexts.
Lessons Learned from PFAS in Groundwater
- 1. Do Patterns of PFAS Distribution Tell Us Something? Lessons Learned from PFAS in Groundwater The logo and ANTEA are registration trademarks of Antea USA, Inc.
- 2. Background The Chaos PFAS/AFFF Facts Our Study - Patterns? Transformations Takeaways Agenda
- 3. Antea Group has a large database of groundwater, drinking water and other media sampling locations at multiple sites for PFAS -More than 2000 wells Background Sites include: • Airports • Fire training centers • Refineries • Landfills • Plastics manufacturing • Metal plating mist suppressant manufacturing • Paper products manufacturing • Petroleum fire sites 25 sites are included in this study 23 of these are sites where AFFF was used
- 5. Using the tools to understand distribution, fate and transport that the environmental industry has developed for BTEX, PCB, and cVOCs, we have been able to: • predict fate and transport • characterize source • occasionally date and/or identify the source Groundwater Database Making Sense out of Chaos
- 7. PFAS - Improvements, research and development leading to: • 2000 - Voluntary discontinuation PFOS • 2002 - TSCA PFOS phase-out • 2003 - AFFF with PFOS no longer sold but still on the shelf • 2015 - TSCA PFOA phase-out PFAS - Different formulations, depending on use: • Textiles – fluoropolymers • Paper - 3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl and 25 others • Biocide – Non polymeric • Teflon – fluoropolymers AFFF - Different formulations PFAS and AFFF What we Know
- 8. Simons electro-chemical fluorination (ECF) process • Generally even and odd numbered, branched and linear chains of perfluoroalkyl compounds • Phased out in the U.S. • Examples: Perfluoroalkyl Groups • Sulfonates (PFOS) • Carboxylates (PFOA) • Sulfonamido (MeFOSAA and EtPFOSA) • Many Unnamed Telomerization process • Produces even-numbered, linear chains • The most common method today • Example Fluorotelomer Groups (ex) • Fluorotelomer alcohols (8:2 FTOH) • Fluorotelomer sulfonic acids (8:2 FTSA) • Fluorotelomer carboxylic acids (6:2 FTCA) PFAS Production Process
- 9. Approximately 90% Sulfonates Approximately 75% Sulfonates AFFF National Academy of Sciences. 2017,Use and Potential Impacts of AFFF Containing PFASs at Airports. Jennifer A. Field, PhD, Oregon State University. http://nap.edu/24800
- 10. • Long shelf-life complicates age-dating • Pre-2000 formulations still on the shelf • Inventories with PFOS sold through 2003 • Military in the process of switching to C6 in 2019-2020 • Other countries still produce long-chain PFAS products • Some PFAS (precursors) undergo biotic and abiotic transformation to terminal degradation products Lack of trends at first glance, but is there something to be learned? PFAS and AFFF What we Know
- 11. Our Study – Patterns?
- 12. AFFF Source Survey Knowns The majority of sites in this study used Brand A AFFF • 9 Sites Brand A • 3 Sites Brand B • 1 Site Brand D • 7 Mixture of Brands A, B, C and/or D • 3 Unknown • 2 Not an AFFF type, not applicable Challenges GW or Soil Brand Source Matching is complex • Age - Degradation of Precursors • Survey – Lack of records • PFAS Fate and Transport - dependent on properties – • properties vary widely among PFAS class • carbon content – partitioning Not perfect
- 13. PFAS Chemical Group Acronym Chemical Name CAS # Chain # Perfluorinated carboxylic acids PFBA perfluorobutanoic acid 375-22-4 4 PFPeA perfluoro-n-pentanoic acid 2706-90-3 5 PFHxA perfluorohexanoic acid 307-24-4 6 PFHpA perfluoroheptanoic acid 375-85-9 7 PFOA perfluorooctanoic acid 335-67-1 8 PFNA perfluorononanoic acid 375-95-1 9 PFDA perfluorodecanoic acid 335-76-2 10 PFUnA perfluoroundecanoic acid 2058-94-8 11 PFDoA perfluorododecanoic acid 307-55-1 12 PFTA perfluorotridecanoic acid 72629-94-8 12 Perfluorinated sulfonates PFBS perfluorobutane sulfonate 29420-49-3 4 PFHxS perfluorohexane sulfonate 355-46-4 6 PFOS perfluorooctane sulfonate 1763-23-1 8 Fluorotelomer sulfonates 6:2 FtS 1-octanesulfonic acid, 3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluoro-, ammonium salt 27619-97-2 6 8:2 FtS -- 39108-34-4 8 Analytes in this Study
- 14. • Used only Brand A • No pattern 1 10 100 1000 10000 100000 1000000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHpA (ng/L) PFHxS (ng/L) PFBA (ng/L) PFPeA PFHxA Cinnabar Airport B-1 Cinnabar Airport B-2 Cinnabar Airport B-3 Cinnabar Airport B-4 Cinnabar Airport B-5 Cinnabar Airport B-6 Cinnabar Airport B-7 Cinnabar Airport CWN-14A Cinnabar Airport CWN-15A Groundwater Airport
- 15. • Radar Diagram limited to (1 carboxylate: 3 sulfonates) • PFOA and PFOS - Most detected compounds and persistent • Dates of restricted manufacturing in U.S. are available • PFBS were introduced as alternatives to the longer chain perfluoroalkyl sulfonates after 2002 • PFHxS were not imported or produced after 2002 in the U.S. • PFBS, a 4-chain and PFHxS, a 6- chain are NOT precursors to PFOS • Remove data with low detections Four Point Radar Diagram Rationale 1 100 10000 1000000 PFOA PFOS PFBS PFHxS Cinnabar Airport B-1 Cinnabar Airport B-2 Cinnabar Airport B-3 Cinnabar Airport B-4
- 16. • Pattern emerges for Brand A at Airport above • Pattern matches two separate training areas at separate locations also using only Brand A • Each site has a unique pattern • All three sites are fire training centers • All appear to be post-2002 AFFF formulations because PFOS is low and PFOA is high • However, PFHxS is high suggesting pre 2002 formulation Possible Pattern? 1 10 100 1000 10000 100000 1000000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Groundwater Results Ecru B-1 Ecru B-2 Fushsia B-3 Fushsia B-4 Cinnabar Airport B-1 Cinnabar Airport B-2 Cinnabar Airport B-3 Cinnabar Airport B-4 Cinnabar Airport CWN-15A
- 17. • Three fire training sites • Combination of Brand A until 2000 and Brand B or C after 2000 • Third site used unknown AFFF Brand but had highest PFOS detections • Samples collected in 2009, pre- TCSA ruling on PFOA, could represent an older AFFF, where the PFOA which is more soluble has migrated away and the PFOS with a tendency to attenuate to carbon in soil remains Another Similar Pattern? 1 10 100 1000 10000 100000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Groundwater Results Sienna B-2 Sienna B-3 Cerise MW-912 Cerise SP-11 Cerise MW-172 Cerise MW-156 Sable MW-1
- 18. • Three other sites • One airport, two fire training sites • Azure Brand A • Sable Brand A and B • Indigo Site – AFFF Unknown had highest PFOS, likely same AFFF • These all appear to be pre- 2000 formulations before voluntary discontinuation of PFOS Trend 1 100 10000 1000000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Groundwater Results Azure B-1 GW Azure B-2 GW Sable MW-3 Indigo BG-4 Indigo MW-2 Indigo MW-3 Indigo MW-4 Indigo MW-5 Indigo MW-7 Indigo MW-8 Indigo MW-10
- 19. • Former paper products manufacturing near to textile • Entirely new pattern emerges, but there is noise Non AFFF Site – Former Paper Products 1 10 100 1000 10000 PFOA PFOS PFBS PFHpA PFHxS PFBA PFPeA PFHxA Groundwater ng/L
- 20. • Unique pattern unlike AFFF • Repeatable – close match between samples • Outlier patterns are at low concentrations • Nearly void of PFHxS and PFBS • PFOS /PFOA ratio suggests pre 2000 formulation Non AFFF Site – Former Paper Products 1 10 100 1000 10000 PFOA PFOS PFBS PFHxS Groundwater ng/L
- 21. Transformations
- 22. 0.01 0.1 1 10 100 1000 10000 PFOA (ng/g) PFOS (ng/g) PFBS (ng/g) PFHxS (ng/g) Soil Results Azure B-1 SL 0-4' Azure B-1 SL 4-8' Azure B-2 SL 0-4' Azure B-2 SL 4-8' Soil/Groundwater Transfers 1 10 100 1000 10000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Groundwater Results Azure B-1 GW Azure B-2 GW
- 23. Soil to Groundwater to Surface Water Class B Fire Transfers 0.1 10 1000 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Groundwater Results Fushsia B-1 Fushsia B-2 Fushsia B-3 Fushsia B-4 1 10 100 PFOA (ng/L) PFOS (ng/L) PFBS (ng/L) PFHxS (ng/L) Surface Water Results Fushsia SW-1 0.01 1 100 PFOA (ng/g) PFOS (ng/g) PFBS (ng/g) PFHxS (ng/g) Soil Results Fushsia B-1 0-4' Fushsia B-1 4-8' Fushsia B-2 0-4' Fushsia B-2 4-8' Fushsia B-3 0-4' Fushsia B-3 4-8' Fushsia B-4 0-8'
- 24. Takeaways
- 25. • Calibrate to a known source type (e.g. test the AFFF) • Not advisable to try pattern matching or to demonstrate lack of match as not same AFFF across different media • Measure the TOC/pH/anions/cations in soil and groundwater • Complete a survey/interview – but not always accurate (SDS trade secrets) • Consider age, distance to source location, other PFAS sources • More study needed (soil and other media patterns evaluated) Lessons
- 26. We do more than effectively solve client challenges; we deliver sustainable results for a better future. Thank you If you have more questions… Jack Sheldon Remediation Expert 515 971 8329 jack.sheldon@anteagroup.com Caron Koll, PG, LSP Consultant 315 416 7450 caron.koll@anteagroup.com Katie Angel EIT 315 949 7036