per and polyfluoroalkyl substances (pfas) challenges and ...copyright © 2018, testamerica.copyright...

Copyright © 2018, TestAmerica. All rights reserved.Copyright © 2018, TestAmerica. All rights reserved.

Taryn McKnight – Product Manager

Per and Polyfluoroalkyl Substances (PFAS)

Challenges and Best Practices

Copyright © 2018, TestAmerica. All rights reserved.

Briefly - What are PFAS?

Synthetic compounds formed from

carbon chains with fluorine atoms

The C-F bond

is one of the

shortest and

strongest in

nature

Toxic

Bio-accumul

ative

Persistent


Nomenclature

PFCs

PFAAs

PFASPer- and Polyfluoroalkyl Substances

Perfluorinated Compounds

Perfluoroalkyl Acids

PFSAs PFCAsPerfluorinated sulfonic acids Perfluoroalkylcarboxylic acids

PFOAPFOS

Completely &

Incompletely

Fluorinated

Completely

Fluorinated

Subset of

PFCs


Carbon Chain Nomenclature

Acronym Compound NameChain

Length

PFDA Perfluorodecanoic acid C10

PFOA Perfluorooctanoic acid C8

PFHxS Perfluorohexanesulfonic acid C6


Chemical Structure

• Chain Length

• Carbon Backbone

• Functional Group


Chemical Structure

• ≥8 carbon atom PFCAs

• ≥6 carbon atom PFSAs Chain Length

• Inert, Persistent & Bioaccumulative

Carbon backbone

• Our ability to capitalize on the desirable qualities

Charged Functional Group


Properties

Fluorocarbon “Tail” = Hydrophobic/Oleophobic

Functional Group “Head” = Hydrophilic


Branched & Linear Isomers


PFAS Formation

ECF Reaction = B&L & Unintended Byproducts

Telomer Reaction: Unintended Byproducts & Precursors

+ + =


Manufacturing

Primary

Secondary

Products

Raw Material

Industrial

Chemicals

Consumer

Products


AFFFDoD

Airports

Refineries

Fire Fighting

Training

&

Emergency

Response


Consumer

Products Manufacturers

Landfills

POTWs

Brownfields

GW Monitoring


Example Uses

Automotive

Textiles

Carpet/Furniture

Paper/Pulp

Metal/Surface

Finishers

Paint

Chemicals

Semiconductor

Mining

Car Washes

Stone Cutting/Sealing


Metal Finishing and PFOS

Products used to suppress the mist generated

from chromium plating baths contain PFOS


Landfill Leachate

1

• Complex matrix

• Wide range of concentrations

2

• More short than long chains

• PFBA/PFBS are dominant

3

• Can represent


Trace chemistry -

biotransformation of precursors in the environment

Exposure Pathways


Human exposure is primarily from:

food (fish), DW, air

Exposure continues:

due to persistence

Half-lives in humans:

2 to 9 years

PFOA/PFOS associated with:

kidney and testicular

cancer, thyroid disease;

toxicology still being

studied

Exposure and Toxicity


Regulatory Timeline

When Who What Happened

2002 USEPA Initiated voluntary phase out of PFOS

2006 USEPA PFOA Stewardship Program initiated

2008 CanadaRegulated and prohibited PFOS

imports to Canada

2009 UNStockholm Convention - adds PFOS

to Annex B

2015 USEPAPFOA Stewardship Program

completed December 31, 2015

May

2016USEPA

PFOS and PFOA Lifetime Health

Advisory Limits 70 ppt combined

http://chm.pops.int/Implementation/IndustrialPOPs/PFOS/Overview/tabid/5221/Default.aspx

https://www.epa.gov/pfas/epa-actions-address-pfas


State Drinking Water Limits

StatePFOA

ppt

PFOS

pptComments

North Carolina NA NA “GenX” 140 ppt

Nevada 667 667AZ, AL, CO,

MD, ME, MA,

MI, NY, RI, WV70 70 Adopted HAL from 2016

Connecticut 70 70Combined limit for: PFNA,

PFHxA, PFOA, PFOS,

PFHpA

Pennsylvania 70 70

Minnesota 35 27

Vermont 20 20

California 14 13 Interim Notification Levels

New Jersey 14 TBD PFNA 13 ppt

U.S. EPA

Health

Advisory

Limit

= 70 ppt

https://pfas-1.itrcweb.org/fact-sheets/


State GW or SW Limits

State PFOA ppt PFOS ppt Comments

Oregon 24,000 300, 000

North Carolina 2,000 NA

Alaska 400 400

Texas 290 560 PCLs for 16 PFCs

Maine 130 560

Pennsylvania 70 70

Rhode Island 70 70

Minnesota 35 27

Vermont 20 20Sum of

PFOA/PFOS,

Michigan 420 11

New Jersey NA NA 10 ppt for PFNA

https://pfas-1.itrcweb.org/fact-sheets/


EPA Method 537

“A Drinking Water Method”

Features Method 537Matrices Drinking WaterSample size 250 mlsHolding times 14/28 days Aqueous Extraction SPE SDVB

AnalysisLCMSMS - no confirmation ion

Branched/Linear Isomers YesQuantitation Internal standardReporting Limits (2 ppt - 40 ppt)

Recovery Correction NoLCS recovery limits 70-130

https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=198984&simpleSearch=1

&searchAll=EPA%2F600%2FR-08%2F092+


Groundwater, Soil, Tissue?

What

method do

we use for

non-potable

water

matrices?


537 “Modified”

DoD

QSM 5.1

EPA

8327

ISO

25101

ASTM

D7979

ASTM

7968

EPA

8328


Regulatory Challenges

Formal Guidance

Screening Levels

Target Analytes

Methods

https://www.epa.gov/pfas/epa-actions-address-pfas


537M - Key Elements Reducing

Variability

Applicable to all matrices

Use available cleanups, rigorous

extraction and centrifugation

Isotope Dilution Quantitation

Use all available labeled

analogues w/ recovery correction

Branched and Linear Quantitation

For all available B/L standards

Use of Secondary Ion Transitions


Sample Analyte TA Lab Expected

Water A PFOA 7.91 7.90

PFOS 3.23 3.00

Water B PFOA 9.01 10.8

PFOS 6.81 6.50

Soil A PFOA 7.00 5.83

PFOS 290 262

Soil B PFOA 14.2 12.0

PFOS 23.5 22.0

Fish A PFOA ND ND

PFOS 19.9 20.6

Fish B PFOA 51.4 50.5

PFOS 49.2 53.7

24 labs submitted

9 Passed

PT Study Results - NMI

https://measurement.gov.au/Publications/ProficiencyStudyReports/Documents/AQA16-06.pdf


Sample

Containers

& Holding

Times

HDPE Bottles

Subsampling more significant than material type

Field Filtering

PFAS can adsorb to

filtration equipment

Hold Times

14/28 for 537

Limited HT studies for NPW/SW

Preser-vation

Ship on ice;

Trizma for

DW samples

only


Managing Artifacts

Field Crew: personal care, clothing, food, visitors, books, tarps

Sampling Equipment: bailers, pumps, tubing,

valves

Sample Collection: wash hands, wear gloves, don’t filter, include field QC


Precursors


PFCA Pattern – MeFOSA Precursor

0

10

20

30

40

50

60

70

80

PFBA

PFPeA

PFHxA

PFHpA

PFOA

PFNA

ppt

PFOA


What Do the Results Mean?

Precursor Pre Post % Oxidation

MeFOSA 32.68 ND 100%

MeFOSAA 19.38 ND 100%

EtFOSAA 18.83 ND 100%

6:2 FTS 31.69 ND 100%

8:2 FTS 26.37 ND 100%

PFCA Pre Post Total

PFBA 24.94 27.16 109%

PFPeA 23.38 28.55 122%

PFHxA 26.49 34.87 132%

PFHpA 23.10 25.14 109%

PFOA 23.72 58.71 248%

Total 122 Total 174


Replacement Chemicals


Legacy

Manufacturers

Original

ChemicalPFOA PFOS PFOS

Replacement

Chemical

HFPO-DA

“GenX”ADONA F-53B


“PFOS-Free” Replacements

Stockholm Convention Guidance

Product Name Ingredient

Fumetrol® 21 *6:2 FTS based

ANKOR® PF1 *6:2 FTS based

Netzmittel LF Chemical structure unknown

Non Mist-L Chemical structure unknown

“ORGANIC FLUOROSULFONATE”

*does not contain perfluorinated compounds

http://chm.pops.int/Implementation/IndustrialPOPs/PFOS/Overview/tabid/5221/Default.aspx