pfas - outlinefrom carbon chains with fluorine attached to these chains. the c-f bond is the...

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

Polyfluorinated Alkyl Substances (PFAS) Challenges and Best Practices

Taryn McKnight – Product Manager

Copyright © 2018, TestAmerica. All rights reserved.

PFAS - Outline

Introduction to PFASsWhat are PFASs?

Nomenclature/ChemistrySources, Timeline, FormationExposure, Toxicity and Risk

Regulatory ReviewEPA and the States

AnalysisAnalytical MethodsData Comparability

Sample Collection & QCPrecursors and TOP Assay

Replacement Chemicals

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What Are Emerging Contaminants?

Pose a real or perceived threat

Not currently regulated

New source has been identified or a new exposure pathway

New detection method or treatment technology has been developed


What are PFAS?

Class of synthetic compounds containing thousands of chemicals formed from carbon chains with fluorine attached to these chains.

The C-F bond is the shortest and the strongest bond in nature.

PFOS and PFOA are fully fluorinated and the most common perfluorinated chemicals (PFCs).

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Metal Finishing and PFOS

Products used to suppress the mist generated from the chromium plating baths contain PFOS.


PFAS Characteristics

Persistent and resistant to degradationFound in soil, air and groundwaterFound in blood samples of humans and wildlife worldwide

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NomenclaturePFAS: Per- and Polyfluoroalkyl Substances

Broad term – completely and incompletely fluorinated

PFC: Perfluorinated Compounds

Subset of PFAS, completely fluorinated

PFOS: Perfluorooctane sulfonate

PFOA: Perfluooctanoic acid


Carbon Chain Nomenclature

Acronym Compound Name Carbon Chain Length

PFUnA Perfluoroundecanoic acid C11

PFDA Perfluorodecanoic acid C10

PFNA Perfluorononanoic acid C9

PFOA Perfluorooctanoic acid C8

PFHpS Perfluoroheptanesulfonic acid C7

PFHxS Perfluorohexanesulfonic acid C6

PFBS Perfluorobutanesulfonic acid C4

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Chemical StructureCarbon chain atoms (C2-C18) surrounded by fluorine atoms

Charged functional group is present at the end, typically a carboxylate or a sulfonate salt or an acid.

Long chain = ≥8 carbon atom PFCAs and ≥6 carbon atom PFSAs Carbon backbone = inert = persistent & bioaccumulative

Charged functional group = our ability to capitalize on the desirable qualities of these chemicals

Perfluoroalkyl Carboxylate

Perfluoroalkyl Sulfonate


PFAS FormationECF Reaction: Process yields a mixture of B/L isomers

C8H17SO2F + 34HF → C8F17SO2F + 17H2

Telomer Reaction: Process yields 100% linear isomers(Synthesis of building blocks leading to fluorotelomer alcohols)

(5 volts)

F(CF2)2I F(CF2)nI F(CF2)nCH2CH2I F(CH2)nCH2CH2OH→ → →Telomer alcoholsPFEI Telomer A Telomer B

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Environmental Exposure Pathways Oliaei, Environ Pollut Res. (2013): 1977-1992


Exposure, Toxicity and Risk

Major source of non-occupational exposure to humans from food and air (predominately fish consumption) Exposure continues beyond phase out, due to persistence.Have half-lives in humans range from 2 to 9 years for PFOA/PFOS PFOA associated with liver, pancreatic,

testicular, and mammary gland tumors in laboratory animals. PFOS causes liver and thyroid cancer in ratsPFOA and PFOS are associated with cancers in humans. Pathways are being studied.

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PFAS – Regulatory TimelineWhen Who What Happened

1980s EU Groundwater directive to prevent discharge of PFOS

2002 US EPA Initiated voluntary phase out of PFOS

2002 3M Discontinued making PFOS (7 other makers complied)

2006 US EPAAnnounced 2010 (95%)/15(100%) PFOA Stewardship Program

2008 Canada Regulated and prohibited PFOS imports to Canada

2009 UN Stockholm Convention - adds PFOS to Annex B

2010 US EPA2010 PFOA Stewardship program - must reduce PFOA use by 95%

2015 US EPA Must 100% eliminate the use of PFOA by December 31,2015.

May 2016 US EPAPFOS and PFOA life time health limits reduced to 70 ppt each or the total if both are present.

Sept 2016 NJ DWQI proposed PFOA drinking water MCL of 14 ppt


State PFOA ppt PFOS ppt Comments Source

Alabama 70 70 EPA

Alaska 400 400 ADEC

California Prop 65 Prop 65 OEHHA

Connecticut 70 70 PFNA, PFHxA, PFPeA, PFHpA DPH

Delaware 70 70 DNRGeorgia 70 70 Proposed DPHIllinois 400 200

Iowa 70 70 DNR

Kentucky 400 200 NKWD

Maine 70 70 ME DEPMaryland 70 70

Michigan 70 70 5ppt TDL MI DEQ

Minnesota 35 27 MDHNew Hampshire 70 70 DES

New Jersey* 14 TBD PFNA 13 ppt NJDEP

New York 70 70

North Carolina 2000 NA DENR

Ohio 400 200 EPA

Oregon 24000 300000 PFHpA, PFNA, PFOSA

Pennsylvania 70 (May lower to 6) 70 PA DEP

Rhode Island 70 70

Texas 290 560 PCLs for 16 PFCs CEQ

Vermont 20 20 VT DOH

Washington NA TBD Listed PFOS as PBT

West Virginia 400 200

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Site History

2007, MN found high levels of PFOS at a WWTP and identified a chromium electroplating facility (Keystone Automotive) as the source.

2008, EPA Region 5 initiated a study of 11 chromium electroplating facilities in IL and OH.

10 out of 11 facilities had PFOS detected in their wastewater in concentrations ranging from 31-39,000 ppt


Regulatory Challenges

Lack of promulgated methods for non DW matrices

Lack of guidance for most matrices and compounds

Wide variety of analytes and limits

Lack of toxicology data for more than a few compounds

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Methods- Current Status

2009 - EPA Drinking Water Method 5372009 – ISO Method 25101 for DW, GW, Surface Water2014 - ASTM D7968-17 for PFC in Soil by LC/MS/MS2015 - ASTM D7979-17 for PFC in Water, Sludge, Influent, Effluent and WW by LC/MS/MS2016 – EPA Method 537 Technical Advisory2017 - DoD QSM 5.1 addresses PFAS


Study Results - NMI PT

Sample Analyte Sac Lab ExpectedWater A PFOA 7.91 7.90

PFOS 3.23 3.00Water B PFOA 9.01 10.8

PFOS 6.81 6.50Soil A PFOA 7.00 5.83

PFOS 290 262Soil B PFOA 14.2 12.0

PFOS 23.5 22.0Fish A PFOA ND ND

PFOS 19.9 20.6Fish B PFOA 51.4 50.5

PFOS 49.2 53.7

24 labs submitted results – 9 PassedTestAmerica passed water, soil and fish tissue samples

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Managing Artifacts

The field crew – personnel hygiene, clothing, food products, sunscreens and insect repellants, detergents

Sampling equipment – avoid fluoropolymer bailers, pump bladders, tubing, valves etc.

Sample collection – wash hands, wear nitrile gloves

Add field QC samples routinely

Avoid food or drink on-site

Limit visitors during sample collection


Replacement ChemicalsOn-going effort to replace long-chain PFAAs

Since 2000s

Advancements in technology Enables them to make

fluoropolymers without PFOA or PFOS

Many alternatives are in use Below regulatory radar

Safe for humans or the environment?Unclear

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Replacement Chemicals

CAS # Name Synonym Manufacturer Use Process

73606‐19‐6 F‐53B (Major component)6:2CL‐PFESA or 9CL‐PF3ONS

Chenguang, China

PFOS replacement TBD

83329‐89‐9 F‐53B (Minor component)8:2CL‐PFESA or 11CL‐PF3OUdS

Chenguang, China

PFOS replacement

TBD

958445‐44‐8 ADONA or DONA NH4ADONA or DONA

NH43M and Dyneon

PFOS replacement

TBD

13252‐13‐6 PFPrOPrA → HFPO‐DA DuPont/ChemoursPFOA

replacementGenX

62037‐80‐3 PFPrOPrA NH4 HFPO‐DA NH4 DuPont/ChemoursPFOA

replacementGenX

3330‐15‐2 PFPrPrA ether HFPO‐DA ether DuPont/ChemoursPFOA

replacementGenX


PFOS-Free Replacements –Stockholm Convention GuidanceProduct Name Ingredient

Fumetrol® 21 (Atotech) *6:2 FTS based

ANKOR® PF1 (Enthone) *6:2 FTS based

Netzmittel LF (Atotech) Chemical structure unknown

Non Mist-L (Uyemura) Chemical structure unknown

“ORGANIC FLUOROSULFONATE”

*does not contain perfluorinated compounds

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PrecursorsWhy We Care & How We Assess Them

Thousands of precursors in industrial & consumer productsSome biotransform to make PFAAs

PFAA Precursors

BiotransformationPFAA

PFOA

PFOS

Precursors PFAAs

Oxidation via TOP Assay


PFCA Pattern – Me-FOSA Precursor

0

10

20

30

40

50

60

70

80

PFBAPFPeAPFHxAPFHpAPFOAPFNA

ppt

PFOA

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What Do the Results Mean?TOP Assay measures total PFCA

Precursor Pre - TOP Post - TOP % OxidationFOSA 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 – TOP Post - TOP TotalPFBA 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


What Conclusions Can We Draw?

PFAA precursors are present in environmental samples

Treatments must remove precursors and end points

Presence impacts risk assessmentsPotentially increases future risk as precursors are biotransformed

Presence impacts our decisions for AFFF formulations

Adopt new manufacturing process

pfas - outlinefrom carbon chains with fluorine attached to these chains. the c-f bond is the...

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