PFAS POLY- AND PERFLUOROALKYL SUBSTANCES · 2017-10-19 · PFAS POLY- AND PERFLUOROALKYL SUBSTANCES...

THE EMERGING ISSUE

PFAS POLY- AND PERFLUOROALKYL SUBSTANCES Big Picture, Challenges and Solutions

June 2017

Ian Ross Ph.D.

Property of Arcadis, all rights reserved

© Arcadis 2016

Contents

Introduction

Chemistry

Products / Sources

Toxicology / Exposure / Risk

Regulatory Evolution

Site Conceptual Model

Investigation Challenges / Advanced Analytical Solutions

Summary


© Arcadis 2017

PFAS Introduction

3

PFAS comprises many thousands of compounds –multiple sources

PFAS are impacting drinking water worldwide

Some PFAS are classed as persistent organic pollutants

Advanced analytical methods are being adopted to measure PFAS

None of the PFASs biodegrade, some biotransform to daughter compounds that are extremely persistent

Dramatically increasing regulatory concern

USES

Where We Find Them and How They’ve Evolved

CONSUMER FFF | ELECTROPLATING |

AEROSPACE MANUFACTURING

BY-PRODUCTS

© Arcadis 2016

Multiple and Varied PFAS Uses

Examples of Common Uses:

• Fluorosurfactant Firefighting foams for Class B (liquid hydrocarbon) fires e.g. Aqueous Film Forming Foams (AFFF), Film Forming Fluoroprotein Foams (FFFP)

• Electroplating mist suppressants

• Semiconductor manufacture

• Pesticides –Insecticides and Herbicides

• Aviation Hydraulic fluids

• Consumer Products

• Oil and water resistant finishes on paper, textiles, carpeting, cookware

• Dyes, Polishes, Adhesives, Lubricants, Inks, Waxes

• Fast-food packaging

• Cleaning agents –detergents, carpet cleaners

• Shampoos and Handcreams


© Arcadis 2016

PFAS Sources

Firefighting Foams

Metal Plating Textiles Electronics Photography Paper Coatings

Paints Hydraulic

Fluids

© Arcadis 2016

Potential Sources

• Defence Sites

• Refineries

• Large Rail Yards

• Chem Facilities

• Commercial and some private airports

• Landfills

• Fire Stations

• Municipal Fire Training Areas

• Plating Facilities

• Biosolids land application

• Coatings / Textiles manufacturers

• Performance Plastics Manufacturers

© Arcadis 2016

Summary Points on PFASs in Paper

• PFAS mainly used in food contact paper meant to contain greasy substances

• Concentrations of PFAS in the materials range between 0.1 mg/kg to ~10 mg/kg

• Paper cups not a major source of PFAS (i.e., coffee cups)

• Fast food wrappers are a major sources of PFAS in food contact materials; also popcorn bags and papers designed for greasy baked items; paper tableware (excluding cups) also likely to contain PFAS

• Long chain PFAS are still very common in China

• Plenty of proprietary replacements to PFAS that advertise as being fluorine free are available

• Other paper applications such as corrosion inhibition paper may contain PFAS, but food contact material contains highest concentrations

From Schaider et al. 2017

© Arcadis 2016

• Fires involving liquid hydrocarbons are class B and extinguished with fluorosurfactant foams such as:

o aqueous film forming foams (AFFF)

o Fluoroprotein (FP)

o Film Forming Fluoroprotein Foam (FFFP)

• AFFF’s were develop in 1960’s and have been used widely to extinguish class B (liquid hydrocarbon) fires

• PFAS foam composition is chemically complex with multiple organofluorine compounds many of which are not detected by commercially available analytical methods (i.e. precursors or polyfluorinated compounds)

• PFAS foams contains both polyfluorinated and perfluorinated compounds

Class B Fire Fighting Foams


© Arcadis 2016

PFAS Foams being Replaced

• C8 (PFOS and PFOA) phased-out

• C8 replaced with compounds with shorter (e.g., C4, C6) perfluorinated chains

• C4, C6 PFAS are less bioaccumulative, still extremely persistent and more mobile in aquifer systems vs C8 - more difficult and expensive to treat in water.

• Solutions for characterizing all PFAS species important to cover current and future risks / liabilities

• Regulations addressing multiple chain length PFAS (long and short) are evolving globally

• Fluorine free (F3) foams contain no persistent pollutants

• F3 foams pass ICAO tests with highest ratings for extinguishment times and burn-back resistance, so are widely available as replacements to AFFF

Non-fluorinated replacement foams are being increasingly adopted

Manufacturer F3 Foam

National Foam Jetfoam (Aviaton)

National Foam Respondol (Class B)

Auxquimia UNIPOL

Vsfocum Silvara

Bioex Ecopol

Fomtec Enviro 3x3 Plus

Solberg Re-healing Foam RF6 / RF3

Dr. Sthamer Moussol F-F3/6

PFAS PROPERTIES AND CHEMISTRY

Parameter PFOS (Giesy, 2010; OECD,

2002)

PFOA (EFSA,

2008)

CAS number 1763-23-1 335-67-1

Chemical formula C7H15COOH

Molar weight 538,23 g/mol 414,07 g/mol

Boiling point n.a. 189-192 °C

Solubility 680 mg/l (pure water)

370 mg/l (fresh water)

12.4 mg/l (sea water)

3400 - 9500 mg/l

Log Kow (octanol/water partitioning

coefficient)

-1.08 Not determined

Henry’s law constant 3.05 x 10-9 atm. m3/mol (pure

water)

4.7 x 10-9 atm. m3/mol (fresh

water)

1.4 x 10-7 atm. m3/mol (sea

water)

Not determined

Vapor pressure 3.31 x 10-4 Pa 4,2 Pa

Density 0.6 kg/l (potassium salt)

1.1 kg/l (ammonium salt)

1.8 kg/l

pKa -2.6 2-3

© Arcadis 2016

PFAS - Properties and Implications

October 18, 2017 12

PFAS plumes are generally longer as PFAS

are generally:

• Highly soluble

• Low KOC

• Recalcitrant – extreme persistence

• Mostly Anionic

Chemical

Properties

PCB

(Arochlor

1260)

PFOA PFOS TCE Benzene

Molecular

Weight 357.7 414.07 538 131.5 78.11

Solubility (@20-

25°C), mg/L 0.0027 3400 – 9500 519 1100 1780

Vapor Pressure

(@25°C),

mmHg

4.05x10-5 0.5-10 2.48x10-6 77.5 97

Henry’s

Constant, atm-

m3/mol

4.6x10-3 1.01x10-4 3.05x10-9 0.01 0.0056

Log Koc 5 – 7 2.06 2.57 2.473 2.13


© Arcadis 2016

Perfluorinated compounds (PFCs)

PFAAs totally resist biodegradation & biotransformation so are extremely persistent

• Perfluorinated Compounds (PFCs) generally are the Perfluoroalkyl acids (PFAAs)

• PFAAs include:

• Perfluoralkyl carboxylates (PFCAs) e.g. PFOA

• Perfluoroalkyl sulfonates (PFSAs) e.g. PFOS

• Perfluoroalkyl phosphinic acids (PFPiS); perfluoroalkyl phosphonic acids (PFPAs)

• There are many PFAAs with differing chain lengths, PFOS and PFOA have 8 carbons (C8) -octanoates

July 2016 13

C1 Methane

C2 Ethane

C3 Propane

C4 Butane

C5 Pentane

C6 Hexane

C7 Heptane

C8 Octane

C9 Nonane

C10 Decane

C11 Unodecane

C12 Dodecane

C13 Tridecane

C14 Tetradecane


© Arcadis 2016

Polyfluorinated Compounds -Precursors

Thousands of polyfluorinated precursors to PFAAs have been commercially synthesized for bulk products

The common feature of the precursors is that they will biotransform to make PFAA’s as persistent “dead end” daughter products

PFAS do not biodegrade i.e. mineralise

Some precursors are fluorotelomers

Some are cationic (positively charged) or zwitterionic (mixed charges) –this influences their fate and transport in the environment

Cationic / zwitterionic PFAS tend to be less mobile than anionic PFAAs and so can potentially be retained longer in “source zones”

Environmental fate and transport will be complex as PFAS comprise multiple chain lengths and charges

PFOA


© Arcadis 2016

© Arcadis 2016 2016

PROPERTY OF ARCADIS, ALL RIGHTS RESERVED 16

Precursors Biotransform to PFAAs In Vivo

© Arcadis 2016 October 18, 2017 17

© Arcadis 2016

Aerobic Biotransformation Funnel –Precursors converted to PFAAs

REGULATORY CLIMATE / PFAS DISTRIBUTION

Evolution of regulatory understanding globally and global distribution


© Arcadis 2016


Human Exposure to PFAS

Drinking water

Food

House dust

Indoor air

Outdoor air

Consumer products

• Fluoropolymers inc. side chain polymers

• Fluorosurfactants

• Performance chemicals

• Product residuals

Main exposure

Precursor

PFAA

© Arcadis 2016

PFAS Exposure, Distribution, and Elimination in Humans

EXPOSURE DISTRIBUTION ELIMINATION

• Most exposure is likely from

ingestion of contaminated food

or water

• Exposure can also comes from:

• Breast milk

• Air

• Dust (especially for

children)

• Skin contact with various

consumer products

• Elimination of PFOS, PFHxS and PFOA from the human body takes some years, whereas elimination of shorter chain PFAS are in the range of days

• Apart from chain length, blood half-lives of PFAS are also dependent on gender, PFAS-structure (branched vs. straight isomers), PFAS-type (sulfonates vs. carboxylates) and species.

• Elimination mainly by urine.

• PFAS bind to proteins, not to fats.

• Highest concentrations are found in

blood, liver, kidneys, lung, spleen

and bone marrow.

• Long chain PFAS such as PFOS,

PFHxS and PFOA have

bioaccumulative properties.

• Shorter chain PFAS generally have a

lower bioaccumulation potential,

although there may be some

exceptions.


© Arcadis 2016

Toxicity for Humans • Exposure mainly by ingestion

• PFAS bind to proteins (not to lipids / fats) and are mainly detected in blood, liver and kidneys

• PFOS: carcinogenity “suggestive” (US EPA, 2014). PFOA: “possibly carcinogenic” (International Agency for Research on Cancer, IARC, 2014)

• Study with 656 children demonstrated elevated exposure to PFOS & PFOA are associated with reduced humoral immune response [1]

• Large epidemiological study of 69,000 persons found probable link between elevated PFOA blood levels and the following diseases: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and preeclampsia –C8 science panel [2]

• European Food Safety Authority (2008) established a TDI for PFOS and PFOA of 150 ng/kg bw/day and 1.500 ng/kg bw/day

• USEPA has selected a Reference Dose for PFOS and PFOA of 20 ng/kg bw/day (May 2016)

[1]

[2] http://www.c8sciencepanel.org/

© Arcadis 2016

Perfluorinated Compounds: Reproductive Toxicity

• Pregnant/breastfeeding mothers are the primary sensitive populations.

• Detected in breastmilk, umbilical cord blood, and amniotic fluid

• At birth infants have roughly equivalent serum levels as mothers.

• Levels in infants increases further after birth from breast milk or from water in formulae

Skeletal Variations

Testicular Cancer

Persistent Liver Effects

Mammary Gland

Development

USEPA Determine Safe Levels for Humans

NOAEL

• USEPA dismissed, New Jersey DWQI included (14ppt target for PFOA)

Chronic toxicity study in rats, PFOA

(Butenhoff et al 2012)

Study of PFOA exposure in mice

during pregnancy (Lau et al. 2006)

Hepatic mitochondrial alteration

in mice following prenatal

exposure to PFOA (Quist et al. 2015)

Mammary gland sensitivity in mice

(Tucker et al. 2015)

© Arcadis 2016 2016 PROPERTY OF ARCADIS, ALL RIGHTS RESERVED 24

Evolving Regulatory PFAS Values – Overview Drinking, Surface and Ground Water (mg/l)

PFOS O=8

PFOA O=8

PFBS B=4

PFBA B=4

PFPeA/S Pe=5

PFHxA Hx=6

DENMARK (Drinking & Groundwater)

FEDERAL GERMANY

(Drinking Water)

(0.1)

UK (Drinking Water)

AUSTRALIA (Drinking Water)

(0.09)

THE NETHERLANDS US EPA (Drinking Water)

VERMONT (Drinking Water)

MINNESOTA (Drinking Water)

NEW JERSEY

CANADA (Drinking Water)

PFHxS Hx=6

PFHpA Hp=7

PFOSA O=8

PFNA N=9

PFDA D=10

COMPOUND REGULATED AND CHAIN LENGTH KEY

(0.07)

ITALY (Drinking Water)

(0.07)

TEXAS-Residential (Groundwater)

0.56

(1)

0.3/ 0.3/

0.3/

0.3/

0.3/

3/

7/

3/ 1/

.03 0.5

0.5

(0.1)

1

0.6 0.2

15

30

0.2 0.2

0.2

0.2

.014 .013

(0.02)

.027 .035

7

7

0.56

0.29

34

71

.093 .093

0.56

0.29 0.37

.093

0.6

.53

.023 ground

drinking

0.5

drinking drinking .01 ground

0.29

SWEDEN (Drinking Water)

(0.5) (0.5)

(0.5) (0.5)

(0.5) (0.5)

5

STATE OF BADEN-WÜRTTEMBERG

(Groundwater)

0.23/(0.3)

European Surface Waters (PFOS) 0.00065

Australian Surface Waters (PFOS) 0.00023

(0.07)

.005 .005

PENNSYLVANIA (Drinking Water

-proposed)

© Arcadis 2016

PFAS in European Surface Waters

July 2016 25


River PFOS (ng/l) Flow(m3/s)

Scheldt (Be, NL) 154 -

Seine (Fr) 97 80

Severn (UK) 238 33

Rhine (Ge) 32 1,170

Krka (Sl) 1,371 50

© Arcadis 2016

European Surface Water Distribution

July 2016 26


© Arcadis 2016 July 2016 27




© Arcadis 2016

International Regulations

July 2016 29


http://chm.pops.int/TheConvention/ThePOPs/ChemicalsPr

oposedforListing/tabid/2510/Default.aspx

© Arcadis 2015 10/18/2017 30


Detected in ~ 2% of large public water supplies

USEPA UMCR 3, May 2016

PFAS in US Public Water Supplies

© Arcadis 2016

PFAS News 2016

© Arcadis 2016

PFAS News


ANALYTICAL TOOLS

© Arcadis 2015

• Detection limits are low (ng/L) so avoid use of fluorinated polymers which can release PFAS (e.g. Teflon) in sampling / analytical methodologies

• Avoid use of glass sampling vessels or metals as PFAS adhere to the surface of glass/metals

• Samples should be collected in polypropylene or polyethylene (HDPE) bottles fitted with an unlined (no Teflon), polypropylene screw cap.

• Avoid any filtering during sample preparation as PFAS adhere to filter matrices

• PFAS stratify in solution as they collect at the air / water interface so consider that:

– sampling from groundwater wells should ideally be from the surface of the water table (AFCEC protocols)

– protocols for working with water samples must include a vigorous shake of the solution before subsampling

• Micro-organisms can degrade precursor molecules making more PFAA’s

Specific specialist sampling protocols required

Sampling Considerations

© Arcadis 2016

• US EPA Method 537: Analysis for selected PFAS in drinking water

• 12 PFAAs and 2 Precursors:

– PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUA, PFDoA, PFTrA, PFTeA

– PFBS, PFHxS, PFOS

– N-EtFOSAA, N-MeFOSAA

• Method 537 has been adapted with more analytes to other media

• Up to 65 individual analytes (laboratory dependent)

• Groundwater with PFAS LODs ranging as low as 0.09 ng/L

• Availability of standards and other factors limit the number of PFAS that can be measured with a single method

• Thousands of precursors and their transient metabolites makes synthesis of a comprehensive set of standards unrealistic

Analysis by LCMSMS via EPA Method 537 or similar

Conventional analysis will not reflect total PFAS mass


© Arcadis 2016

18 October 2017 Useful Graphics 37

• Total oxidizable precursor (TOP) Assay

– Initial LC-MS/MS analysis with re-analysis following oxidative digest

– Detection limits to ~ 2 ng/L (ppt)

– Commercially available in UK, Australia, under development in US

• Particle-induced gamma emission (PIGE) Spectroscopy

– Isolates organofluorine compounds on solid phase extraction,

measures total fluorine

– Detection limits to ~ 15 ug/L ( ppb) F

– Commercially available in US

• Adsorbable organofluorine (AOF)

– Isolates organofluorine compounds with activated carbon and

measures F by combustion ion chromatography

– Detection limits to ~ 1 ug/L (ppb) F

– Commercially available in Germany, Australia

• Time of Flight MS (LCQTOF) MS – Identifies multiple precursors via mass ions capture and accurate mass

estimation (to 0.0001 of a Dalton) to give empirical formulae (e.g.

C10F21O3N2H4)

Advanced Analytical Techniques Expanding analytical tool box to assess total PFAS


© Arcadis 2016

Total Oxidizeable Precursor Assay (TOP) Oxidation of Precursors to PFAAs with OH

S2O82- 2 SO4

-

Heat

OH-SO4

2- + OHpH>11

NaOH + K2S2O8

Dilute

Sample

pH >12

85 oC

OH•

Approach described in Houtz and Sedlak, ES&T, 2012

R + shorter PFAA

products

PFSA

Precursors

PFCA

Precursors

OH• PFPA

Precursors + 8

8

8

OH•

OH•


© Arcadis 2016

Total Oxidizable Precursor (TOP) Assay Fire Training Area Soil Composite

Groundwater Composite

240%

increase

75%

increase

EPA Method 537 Underestimates the PFAS Mass

© Arcadis 2016

Digest AFFF precursors and measure the hidden mass: TOP Assay

Analytical tools fail to measure the hidden PFAS precursor mass, the TOP assay solves this

Microbes slowly make simpler PFAA’s (e.g. PFOS / PFOA) from PFAS (PFAA precursors) over 20+ years

Need to determine precursor concentrations as they will form PFAAs

Too many PFAS compounds and precursors –so very expensive analysis

Oxidative digest convert PFAA precursors to PFAA’s

Indirectly measure precursors as a result of the increased PFAAs formed


© Arcadis 2015

October 18, 2017 41



Conceptual Site Model

© Arcadis 2017

Excessive Costs

October 18, 2017

44

http://greensciencepolicy.org/wp-

content/uploads/2016/09/Rolland-Weber-PFOS-

PFAS-German-activities-Final.pdf

Risk based approaches not adopted in Germany

© Arcadis 2015

Conceptual Site Model

© Arcadis 2015

Groundwater Risks to Receptors

AFFF / FFFP / FP

Fire training

Incident Response Source – Pathway – Receptor

High concentration, spill site, route

via groundwater to receptor e.g.

drinking water well

Diffuse

Ground level impacts and

ground/surface water

Landfill Leachate

Municipal / Domestic WWTP

Industry & Manufacturing

Agricultural Land

Commercial / Domestic Products

Metal Plating

ASTs –Fuel storage (FFFP / FP)

Grasshopper effect

via widening of source zones

e.g. concentrated plume intercepts crop spray irrigation to make secondary wider source area for more dilute plume

?

?

?


Increasing mobility of shorter perfluoroalkyl chain PFAS

C6 C4 C5 C3? C2?

C8 C7 C6 C4 C5 C3? C2? Hidden anionic mobile PFAA

precursors

Anionic precursor biotransformation

increases as aerobic conditions develop

Direction of groundwater flow

Anionic PFAA

dead end

daughters

0

0

C F S

0 8 17

0

0 0 H3C

0

C 4H9

0

C8F17 S 0

0

0

0 0 H3C

0

C 4H9

0

0

S

0 C8F1

7

C

F

0

0

S

0 8 17

0

0

C6F1

3

S 0

0

0

C8F1

7

0

0

S

0

S

0 C8F1

7

0

0

S

0 C8F1

7

0

S

0 C8F1

7

0

0

S 0

C6F1

3

0

C6F1

3

0 0

0

S 0 S 0

0

C

6F13

Source Zone - Hidden Cationic and Zwitterionic Precursors Less mobile as bound via ion exchange to negatively charged fine grain soils

(e.g. silts & clays). Precursor biotransformation is limited by the anaerobic redox

conditions created by the co-occuring hydrocarbons.

F

N+

0

0H

0

0 0

C1H9

C F

H3C 0

0

0

S 0 8 17

0

0

S

N H

C 8F17

NH +

F

F C n

0

0 0H

N S

F

F C

F n 0

0

H3C 0 0 C 4H9

0

0H

0

N+ F

F

F C

F

C6F13

0

0

S 0 N

N N

S

0 H

0

F

F C

F n

0

0- C5F11

0

H3C 0

0

0 0 H3C 0

C 4H9

0 C4H9

0 0

C6F17 S 0

0

CH

CH

CH

CH CH

CH

CH

AFFF/FFFP/FP

CH3

CH 3

CH3

CH3

CH 3

Hydrocarbon NAPL Short hydrocarbon plume

-300mV -200mV REDOX

ZONATION -100mV 0mV 100mV 200mV

C7 C8

PFAS Source Zones, a CSM




Total molar concentration of PFAA precursors

© Arcadis 2015

Summary - PFAS Management..

• Better site characterisation

• Assess contaminants comprehensively – TOP assay

• Develop intelligent CSM

• Use of detailed site specific quantitative risk assessment

• Consider more sustainable risk management solutions

• Address public risk perception

© Arcadis 2015 10/18/2017 51

© Arcadis 2017

Ask Us About These New Resources!

52 October 18, 2017


Download at: https://www.concawe.eu/publications/558/40/Environmental-fate-and-effects-of-poly-and-perfluoroalkyl-substances-PFAS-report-no-8-16

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PFAS POLY- AND PERFLUOROALKYL SUBSTANCES · 2017-10-19 · PFAS POLY- AND PERFLUOROALKYL SUBSTANCES...

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