Presented by Jack Sheldon at the Groundwater Solutions: Innovating to Address Emerging Issues for Groundwater Resources Conference in Arlington, Virginia.

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

4. 1
10
100
1000
10000
100000
1000000
PFOA
PFOS
PFBS
PFHpA
PFHxS
PFBA
PFPeA
PFHxAThe Chaos

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

6. PFAS/AFFF Facts

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