the analysis of per and polyfluorinated alkyl substances

Copyright © 2018, TestAmerica. All rights reserved.

2018 TCEQ Trade Fair – PFAS Presentation


The Analysis of Per and Polyfluorinated Alkyl Substances (PFAS) Challenges and Best Practices

Karla Buechler – Corporate Technical Director


PFAS - OutlineIntroduction to PFASsWhat are PFASs?Nomenclature/ChemistrySources, Timeline, FormationExposure, Toxicity and RiskRegulatory ReviewAnalytical Best PracticesAnalytical Methods reviewWhy so much variability?How do we reduce variability?New In Line SPE CapabilityFuture Concerns – TOP AssayAlternative chemicals – GenXCapabilities and Questions?

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Briefly - What are PFASs?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).

Persistent and resistant to degradation Found in soil, air and groundwater..

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NomenclaturePFAS – Broad term – completely

and incompletely fluorinated PFC – Subset of PFAS

completely fluorinated compounds. PFOS and PFOA are PFCs (no hydrogen atoms)

PFAAs – Perfluoroalkyl acids – 2 classes PFCAs and PFSAs

AFFF – Aqueous Film Forming Foam –mixture of PFCAs, PFSAs, and PFAA precursors

Fluorochemicals and telomers

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Chemical StructureWhy is it Important?

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Perfluoroalkyl Carboxylate

Fluorotelomer Sulfonates

Perfluoroalkyl SulfonatePerfluoroalkyl Sulfonamido Amines

Perfluoroalkyl Sulfonamido acetic acid amine


Primary Sources – Point or Direct

Released in large quantities from primary manufacturing facilities

Secondary Manufacturing –incorporation of PFC raw materials into industrial and consumer products

The use of AFFFs to fight fires is a direct pathway to the environment –(Connection to DoD)

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Secondary Sources -Indirect Commercial and

consumer products have a finite lifetime. Dispose to landfillsWWTP Air emissions

Trace chemistry –transformation mostly degradation by-products (TOP Assay)

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

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Exposure, Toxicity and Risk

Major source of non-occupational exposure to humans is from food and air (predominately fish consumption)

Human and wildlife exposure can continue even though the chemicals are no longer in use, due to persistence.

PFOS and PFOA have half-lives in humans ranging from 2 to 9 years, depending on the study.

PFOA associated with liver, pancreatic, testicular, and mammary gland tumors in laboratory animals. PFOS causes liver and thyroid cancer in rats

PFOA and PFOS are associated with cancers in humans. Pathways are being studied.

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Regulatory Challenges and New Developments

Lack of regulatory guidance for most matrices and most PFAS compounds

Wide variety of detection limits and analyte lists

Lack of published methodsWhat is Method 537M?What are the ASTM

Methods?What is the ISO Method

25101?


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 EPA PFOS 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

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What started happening in 2016?


What’s Up in New Jersey? (12/2017)

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State PFOA ppt PFOS ppt Comments SourceAlabama 70 70 EPA

Alaska 400 400 ADECCalifornia Prop 65 Prop 65 Proposed 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 NKWDMaine 70 70 ME DEP

Maryland 70 70Michigan 5 proposed 5 proposed MI DEQ

Minnesota 35 27 MDHNew Hampshire 70 70 DES

New Jersey* 14 13 NJDEP

New York 70 70North 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 70Texas 290 560 PCLs for 16 PFCs CEQ

Vermont 20 20 VT DOH

Washington NA TBD Listed PFOS as PBT

West Virginia 400 200


Why are PFAS an Analytical Challenge?

Globally distributed Present at low

concentrations and high Contamination and analyte

loss at all stages of collection and analysis

Lack of authentic standards Unusual physical and

chemical properties Lack of consensus “best”

method for non-DW


PFAS Analytical Methods-Best Practices Manufacturer’s methods were

adopted by the environmental industry – SW-846 Method 8321

EPA expanded manufacturer’s method for drinking water-Method 537

Labs had to modify Method 537 in order to meet client needs for additional matrices

Sept 2016 EPA- Method 537 Technical Advisory

January 2017 DoD QSM 5.1 addresses PFAS

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Why so much method variability? Inconsistent quantitation of branched and linear isomers Absence of multi-lab validated methods Limited certification programs Differences in extraction efficiencies – analyte sorbent dependent External, internal and isotope dilution quantitation schemes Lack of proven commercially available PT samples Use of different isotopically labeled extraction surrogates Lack of commercially available standard materials and true second

sources Target analyte losses during filtration Absence of demonstrated cleanup techniques for complex matrices Wide variety of container types and holding times

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Show Branched and Linear Error in PFOS and PFOA

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Standard

Sample0.99 vs 1.20 ng/ml

B and L L only


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

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24 labs submitted results – 9 Passed

TestAmerica passed water, soil and fish tissue samples


Sample Collection and Holding Time Studies

Samples should be collected in HDPE bottles fitted with unlined (no Teflon) polyethylene screw caps.

In addition, the sampler should avoid contact with fluoropolymers, aluminum foil, and food wrappers.

Samples should not be field filtered.

Samples must be shipped chilled Limited HT study data

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Managing Artifacts The field crew – personnel hygiene,

clothing, food products, sunscreens and insect repellants

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

Sample collection – wash hands, wear nitrile gloves, do not filter samples, add field QC samples routinely

Avoid detergents Avoid food or drink on-site Limit visitors during sample

collection


Sources of Artifacts

USEPA Study, March 2009 EPA/600/R-09/033


Managing Loss/Adsorption

Many PFAS are surface active, which cause them to stratify, adsorb to surfaces

Extraction type – whole bottle or subsample play a more significant role then material type

PFAS can adsorb to the filtration equipment. PFAS in the dissolved phase can also adsorb to the filter material

Unless the samples are analyzed immediately adsorption to glass vials may occur


How can we mitigate analytical variability? Apply tandem mass

spectrometry technology Implement an isotope

dilution quantitation scheme

Compensate for losses with matrix recovery correction

Share our knowledge Invest resources in multi-

lab validation

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What is Isotope Dilution?

Most accurate and precise calibration method available

Partial loss of analyte during preparation is compensated for since chemical interferences are not an issue

Allows for matrix recovery correction – what affects the native analyte will equally affect the isotope

Correction for signal drift Improved qualitative

identification – RT shifts

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What is it? Dilute a water sample with

methanol and inject a large volume onto a modified UPLC

What are the advantages? Simplicity – reduced sample

manipulation Reduced sample volume (5 mls) Speed, reduced TAT Increased capacity Reduced risk of laboratory

background artifacts

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Method 537M – In Line SPE


What are Precursors and Why Do We Care? Thousands of precursors

used in industrial and consumer products

Some biotransform to make PFAAs

Some are fluorotelomers Most are ionic, either

positive, negative or both Fate and transport –

complex process


What is the TOP Assay?

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A new PFAS sample preparation technique

Quantified Transformation

Unknown Potential

Conceptually simple chemistry

Used with 537M not 537

Pre and Post results

Indicates unidentified PFAS


How Does it Work in the Environment?

Low levels of discrete compounds are detected

High levels of discrete compounds are detected, which can include PFOA and PFOS

PFAA PrecursorsBiotransformation

PFOA

PFOSOutflow

PFAA

Inflow

Give me an example:

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TOP – How Does it Work in the Laboratory?

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PFAA Precursors OH•

OH•OH•

PFOA + other PFCAs85°C

85°C


PFCA Pattern – Me-FOSA Precursor

0

10

20

30

40

50

60

70

80

PFBA

PFPeA

PFHxA

PFHpA

PFOA

PFNA

ppt

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PFOA


PFCA Pattern – 8:2 FTS

0

10

20

30

40

50

60

70

80

90

100

PFBA

PFPeA

PFHxA

PFHpA

PFOA

PFNA

PFHpA

ppt

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What Do the Results Mean?

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TOP Assay measures total PFCAPrecursor Pre - TOP Post - TOP % Oxidation

FOSA 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 and many AFFF products Implies treatment strategies must

remove precursors and end points Presence impacts our treatment

strategies and our risk assessments Potentially increases future risk as

precursors are biotransformed Presence impacts our decisions for

AFFF formulations AFFF manufacturers should reduce

the content of PFOA etc.

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Fluorinated Replacement Chemicals

Since 2000, on-going industrial transition to replace LC PFCAs, PFSAs and precursors

Many alternative chemicals are in use – below regulatory radar

Unclear whether they are safe for humans or the environment

DuPont developed patented GenX technology - enables them to make fluoropolymers without PFOA

GenX is not a chemical it is a process


Replacement ChemicalsCAS # Name Synonym Source Use Manufacturer

73606‐19‐6 F‐53B (Major component)

6:2CL‐PFESA or 9CL‐PF3ONS TBD PFOS replacement

chemical Chenguang, China

83329‐89‐9 F‐53B (Minor component)

8:2CL‐PFESA or 11CL‐PF3OUdS TBD PFOS replacement

chemical Chenguang, China

958445‐44‐8 ADONA or DONA NH4

ADONA or DONA NH4 TBD PFOS replacement

chemical 3M and Dyneon

13252‐13‐6 PFPrOPrA HFPO‐DA GenX PFOA replacement chemical DuPont/Chemours

62037‐80‐3 PFPrOPrA NH4 HFPO‐DA NH4 GenX PFOA replacement chemical DuPont/Chemours

3330‐15‐2 PFPrPrA ether HFPO‐DA ether GenX PFOA replacement chemical DuPont/Chemours


TestAmerica Capabilities TestAmerica Sacramento is EPA

approved for Method 537 in drinking water and ISO 25101 in NYS

Sacramento is QSM 5.1 Table B-15 approved for Method 537M

Sacramento, Denver and Burlington Labs are NELAP approved for Method 537M.

7 LCMSMS instruments capable of PFAS testing

Sacramento has successfully implemented the TOP Assay

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Future Concerns

We need a consensus “best” method.

Analyte lists are growing for discrete methods, may lead to forensics.

LC PFASs are being replaced by SC PFASs and little is know about the toxicity

On-going data variability must be improved

We need an effective field screening technique.

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

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The Analysis of Polyfluorinated Alkyl Substances (PFAS) Including PFOS and PFOA

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the analysis of per and polyfluorinated alkyl substances

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