poly- and perfluoroalkyl substances (pfas)... · poly- and perfluoroalkyl substances (pfas) big...

POLY- AND PERFLUOROALKYL SUBSTANCES (PFAS)Big picture, challenges and solutions

May 2016

Dr. Ian Ross

Arcadis UK

© Arcadis 2015

Contents

PFAS News

PFAS Uses & History

PFAS Chemistry

Toxicology

Regulatory Evolution

Analytical Challenges / Advanced Analytical Solutions

Fate and Transport / Site Conceptual Model

Remediation Options

Summary

© Arcadis 2015

• Poly- perfluoroalkyl substances (PFAS) comprises a family of approx. 6,000 fluorinated organic compounds, with PFOS, PFOA representing just two compounds in a complex mixture

• Environmental regulations on PFAS are evolving globally with drinking water standards at ppt/ ng levels and Environmental Quality Standards set very low 0.65 ng/l in Europe

• Aqueous film forming foams (AFFF) contain a complex mixture of PFAS including precursors to PFOS and PFOA which are not currently measured by conventional commercial analysis

• Some PFAS are classed as –persistent organic pollutants (PoPs) and restricted under Stockholm Convention as they are Persistent, Bioaccumulative & Toxic

• PFAS do not biodegrade, but do biotransform to persistent daughter compounds such as PFOS and PFOA which are water soluble and mobile in groundwater so can form very large plumes

• Historically chemical analysis has only focused on a very limited number of PFAS compounds characterized in a few PFAS products

• Remediation has been limited to incineration or stabilisation of soils and pump and treat with GAC for PFOS/PFOA

• Arcadis employs advanced analytical tools to measure entire PFAS mass and unique remediation solutions to destroy PFAS on site or in situ

PFASAccelerating Emergence as Global Contaminants

© Arcadis 2015

PFAS News 2015 / 2016

Detections of PFAS in drinking water has caused spiraling regulatory concern

© Arcadis 2015

PFAS News 2016

© Arcadis 2015

PFAS News June 2016

© Arcadis 2015

https://ing.dk/artikel/forskere-alle-advarselslamper-blinker-fluor-stoffer-163759

Scandinavian News 2013

https://ing.dk/artikel/forskere-alle-advarselslamper-blinker-fluor-stoffer-163759

© Arcadis 2015

https://ing.dk/artikel/hver-tredje-svensker-drikker-vand-med-skadelige-fluorstoffer-171434


https://ing.dk/artikel/hver-tredje-svensker-drikker-vand-med-skadelige-fluorstoffer-171434

© Arcadis 2015

https://ing.dk/artikel/derfor-blev-fluorstoffer-i-drikkevandet-en-af-sveriges-vaerste-miljoesager-

170652


https://ing.dk/artikel/derfor-blev-fluorstoffer-i-drikkevandet-en-af-sveriges-vaerste-miljoesager-170652

© Arcadis 2015

https://ing.dk/artikel/giftige-fluorstoffer-fundet-i-grundvandet-170585


https://ing.dk/artikel/giftige-fluorstoffer-fundet-i-grundvandet-170585

© Arcadis 2015

Multiple and Varied PFAS Uses

Examples of Common Uses:

• Consumer Products

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

• Aqueous film forming foams (firefighting)

• Electroplating mist suppressants

• Semiconductor manufacture

• Aerospace and electronics applications

© Arcadis 2015

Major Locations of PFAS Contamination

• Dept. of Defense Sites

• Refineries

• Large Rail Yards

• Chemical Facilities

• Commercial and private airports

• Municipal Fire Training Areas

• Landfills

• Fire Stations

• Plating Facilities

• Biosolids land application

© Arcadis 2015

Historical Perspective on PFAS

2009: The Stockholm Convention classes PFOS as a Persistent Organic Pollutant and add it to Annexe B to restrict it’s use.

2006: Eight major manufacturers commit to phase out PFOA by 2015 as part of U.S. EPA PFOA Stewardship Program

2013: After 7 years of research, C8 Science Panel determines probable link between PFOA exposure with ulcerative colitis, high cholesterol, pregnancy-induced hypertension, thyroid disease, and kidney and testicular cancer.

1938: Roy Plunkett discovers polytetrafluoro-ethylene (PTFE)

1954: Production of first PTFE-coated, non-stick cookware.

1949: Products containing PTFE first used for coatings of pipes and leak proofing of pipe connections.

1956: Products

containing

perfluorooctane

sulfonic acid (PFOS)

become a popular

treatment for

clothes, carpets,

and furniture.

1968: U.S. Navy develops first PFAS-containing firefighting foams known as AFFF in response to catastrophic ship fires.

2008: The European Food Safety Authority establishes “tolerable daily intake” for PFAS.

1997: PFOS ubiquitously detected in blood bank samples from non-occupationally exposed people around the world

1978: Manufacturers become aware of C8 PFAS in blood of their manufacturing workers

2002: The primary global manufacturer of PFOS phases out PFOS production and related chemistries

© Arcadis 2015

Recent Acceleration of Attention on PFAS

May 2015: Hundreds of prominent scientists and professionals sign on to the Madrid Statement, urging a complete move away from PFAS chemistry.

January 2016: Manufacturing facility in Hoosick Falls, NY named first PFAS-related Superfund site for PFOA-contaminated drinking water

2015: Phase-out of PFOA completed by eight leading manufacturers as part of US EPA Stewardship Council.

October 2015: A manufacturer was found liable for a woman’s kidney cancer in its first of 3500 personal lawsuits related to PFOA contamination of drinking water near a manufacturing facility in Parkersburg, WV.

2015: U.S. EPA UCMR3 sampling of public drinking water finds PFAS in 97 public drinking water supplies.

2016: Stockholm Convention to add PFOA as a Persistent Organic Pollutant.

February 2016: Guernsey, a Channel Island, loses lawsuit against a manufacturer in pursuit of costs related to cleanup of PFOS-contaminated groundwater and soil.

May 2016: US EPA announces drinking water health advisory limit for PFOS and PFOA (separately or combined) at 70 ppt (ng/L)

© Arcadis 2015

PFAS - Properties and Implications

04 July 2016 15

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 Weight357.7 414.07 538 131.5 78.11

Solubility (@20-

25°C), mg/L0.0027 3400 – 9500 519 1100 1780

Vapor Pressure

(@25°C), mmHg4.05x10-5 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 2015

Aqueous Film Forming Foam (AFFF)

• AFFF’s have been used to extinguish class B (liquid hydrocarbon) fires since the 1960’s

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

• AFFF contains both polyfluorinated and perfluorinated compounds

• The term PFAS (poly- and perfluoroalkylsubstances) is being used to describe all the organofluorine compounds in AFFF

• Polyfluorinated precursor compounds biotransformto make perfluorinated compounds which are extremely persistent

• Perfluorinated compounds in AFFF (i.e. PFOA, PFOS) are extremely Persistent, Bioaccumulativeand Toxic (PBT) so are restricted under Stockholm convention and classed as persistent organic pollutants (POPs)

© Arcadis 2015

Beyond PFOS and PFOA

The diversity of PFAS compounds is much broader than just PFOS and PFOA. Assessing just PFOS / PFOA will miss the bigger picture

• PFOS and PFOA are the most well-known forms of the class of PFAS, but they are not the whole story.

• PFOS and PFOA (C8’s) have generally been replaced with shorter perfluoroalkyl chain forms (C6, C4 etc.) which show diminished bioaccumulation potential

• There are additional perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulphonates (PFSAs), collectively termed PFAA’s (perfluoroalkyl acids) approx. major chain lengths ~C2-C10 (PFCAs) ~C4-C12 (PFSA’s)

• There are many more precursors to PFAA’s in addition to the PFAA’s themselves –polyfluorinated compounds.

• There are thousands of PFAS species that naturally biotransform to make PFAA’s with varying perfluoroalkylchain length (including PFOS and PFOA) - these additional PFAS compounds are rarely measured

© Arcadis 2015

Perfluorinated Compounds

Compounds where every carbon is bonded to fluorine, generally C2 to C16 compounds, but focus has been C8 chemistry i.e. octanoates

In May 2009 PFOS was included in Annex B of the Stockholm Convention on persistent organic pollutants

The European Union practically banned the use of PFOS in finished and semi-finished products in 2006 (maximum content of PFOS: 0.005% which was lowered to 0.001% in 2010).

Use of PFOS for industrial applications (e.g. photolithography, mist suppressants for hard chromium plating, hydraulic fluids for aviation) was exempted

The EU intends to back a global ban on perfluorooctanoic acid (PFOA) and its compounds (25 March 2015)

Perfluorinated sulphonates and carboxylate compounds are collectively termed perfluoroalkyl acids (PFAA’s) and are extremely persistent -totally non-biodegradable

PFOA

PFOS

© Arcadis 2015

Polyfluorinated Compounds

Compounds where every carbon is not bonded to fluorine (contains some C-H bonds)

Fluorotelomers e.g. 6:2 or 8:2 fluorotelomer alcohols

Still manufactured and used in certain AFFF

Break down in the environment to form perfluorinated compounds which persist e.g. 8:2 FTS forms PFOA

Pose potential risk to drinking water resources

Less toxicological data available than for PFOS & PFOA

Will biotransform to make PFAA’s as dead end daughter products

PFOA

© Arcadis 2015

Precursors

Precursors are classed as compounds that have the potential to degrade into long chain perfluoroalkylacids (PFAA’s) generally PFCA’s will form

Precursors are generally polyfluorinated compounds and those that form short chain PFAAs will also exist

There are potentially hundreds of compounds in AFFF formulations which can degrade to form perfluorinated compounds

For examples PFOS precursors include N-methyl perfluorooctane sulfonamidoethanol (N-MeFOSE) and N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE)

About 50 precursors were named in the 2004 proposed Canadian ban on PFOS

Precursors biotransform to give PFAA’s as “dead end” persistent daughter products

© Arcadis 2015

Aerobic Biotransformation Funnel

Hundreds of Common

Intermediate

Transformation

Products

Approximately 25 PFSAs,

PFCAs, PFPAs –

collectively termed PFAA’s

All Polyfluorinated / PFAA

Precursor Compounds in

Commerce (“Dark Matter”)

Thousands of PFAA Precursors

Biodegradation of PFAS is

not observed as they

biotransform to produce

PFAA’s as dead end

daughter products that

exhibit extreme persistence

as they do not biodegrade

PFAS compounds do not biodegrade –i.e. mineralize, they biotransform and many parent or intermediate compounds are not detected by conventional analytical methods

© Arcadis 2015

PFAS Manufacturing

• In most of the U.S. and Europe, C8 PFAS species (PFOS and PFOA) have been phased-out due to potential health concerns

• PFOS (C8) and PFOA (C8) and related PFAS have been replaced with compounds with shorter (e.g., C4, C6) perfluorinated chains

• Shorter chain replacement chemicals are typically less bioaccumulative, but they are still extremely persistent and more mobile in aqueous systems vs C8.

• Solutions for characterizing all PFAS species are imperative; multiple carbon chain lengths are present in most environmental samples and even in historical “C8” products

• Regulations addressing multiple chain length PFAS are evolving globally

Non-fluorinated replacement foams are being increasingly adopted

Manufacturer Foam

National Foam Jetfoam (Aviaton)

National Foam Respondol (Class B)

Bioex Ecopol

Fomtec Enviro 3x3 Plus

Solberg Re-healing Foam RF6 / RF3

Dr. Sthamer Moussol F-F3/6

© Arcadis 2015

Perfluorinated carboxylates in consumer products2007-2008

Pre-Treated Carpet

Treated Home Textiles

Food contact paper

Non-stick cookware

• Focus has mainly been on PFOA and PFOS, but PFAS-containing products typically contain a mixture of species in a single product

• C5 to C12 perfluorinated carboxylates are present in many PFOA (C8)-containing consumer products

• Similar diversity of PFAS chain lengths, as well as structures, may be expected in other PFAS-containing products and PFAS-contaminated areas.

Data from Guo et al. 2009, U.S. EPA; Polyfluorinated substances and perfluorinated sulfonates were not measured

© Arcadis 2015

Opinions on Short Chain PFAS

4 July 2016Useful Graphics 27

© Arcadis 2015

PFAS Exposure, Distribution, and Elimination in Humans

EXPOSURE DISTRIBUTION ELIMINATION

• Most exposure is likely from

ingestion of contaminated food

or water

• Exposure also comes from:

• Breast milk

• Air

• Dust (especially for

children)

• Skin contact with various

consumer products

• Elimination of PFOS 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.

• PFOS and PFOA have

bioaccumulative properties.

• Shorter chain PFAS generally have a

lower bioaccumulation potential,

although there may be some

exceptions.

© Arcadis 2015

Toxicity

• Several human epidemiological studies show inconsistent results. Elevated levels of PFOS and PFOA are associated with increaes in blood cholsterol and liver damage. It is however not clear, if these effects are caused by PFAS.

• Based on results of chronic studies with animals (mainly mice, rats and monkeys), there are concerns that PFOS and PFOA cause effects on the liver, lipid metabolism, immune response, reproduction and development.

• Extrapolation from animals to humans is difficult, as humans and animals react differently to PFAS.

• The C8 Science Panel determined a probable link between high levels of PFOA exposure and kidney and testicular cancer

• Toxicity of PFAS other than PFOS and PFOA have not been well-characterized.

http://www.c8sciencepanel.org/

http://www.c8sciencepanel.org/

© Arcadis 2015

PFAS Exposure Pathways

The PFAS web Oliaei et al. Environ. Sci. Pollut Res (2013) 20: 1977-1992

Multiple exposure pathways for PFAS compounded via bioaccumulation / biomagnification

© Arcadis 2015

Target Regulatory PFAS Values

Drinking Water Criteria in µg/l in European Countries

PFOS PFOA PFOSA PFBS PFBA PFPeA PFHxA PFHpA PFNA PFDA 6:2 FTS PFHpS PFHxS PFPeS

Denmark (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) - (0.1) -

Germany 0.3 0.3 - - - - - - - - - - - -

The Netherlands 0.53 - - - - - - - - - - - - -

Sweden 0.09 0.09 - 0.09 - - - - - - - - - -

U.K. 0.3 0.3 - - - - - - - - - - - -

Drinking Water Criteria in µg/l U.S.


Minnesota 0.3 0.3 - 7 7 - - - - - - - - -

New Jersey - 0.04 - - - - - - 0.013 - - - - -

Vermont 0.02

U.S. EPA 0.07 0.07 - - - - - - - - - - - -

Canada 0.3 0.7 - - - - - - - - - - - -

Groundwater Criteria in µg/l in European Countries


Denmark (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) (0.1) - (0.1) -

Germany - - - - - - - - - - - - - -

State of Bavaria 0.23 - - 3 7 3 1 0.3 0.3 0.3 - - - -

State of Baden0.23 0.3 - 3 7 3 1 0.3 0.3 0.3 0.3 0.3 0.3 1

Württemberg

The Netherlands 0.023 - - - - - - - - - - - - -

Groundwater Criteria in µg/l in U.S.


New Jersey - - - - - - - - 0.02 - - - - -

Texas, Residential 0.56 0.29 0.29 34 71 1.9 1.9 0.56 0.29 0.37 - - 1.9 -

Soil Criteria in mg/kg in European Countries, U.S.


Denmark (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) - (0.4) -

Germany - - - - - - - - - - - - - -

State of BavariaEvaluation for pathway Soil -> Groundwater is based on Leachate Concentrations (µg/l)

Evaluation for recycling of Soils is based on LAGA M20 Criteria

The Netherlands 0.0032 - - - - - - - - - - - - -

Texas, Residential 1.5 0.6 0.058 73 150 5.1 5.1 1.5 0.76 0.96 - - 4.8 -

Values in parentheses refer to PFAS regulated as a sum concentration

Drinking water

Denmark ∑12 PFAS* 100 ng/l

Sweden ∑ 7 PFAS ** 90 ng/l

*∑12 PFAS:

PFBS PFHxS PFOS PFOSA 6:2 FTS PFBA

PFPeA PFHxA PFHpA

PFOA PFNA PFDA

**∑ 7

PFAS:

PFBS PFHxS PFOS PFPeA PFHxA PFHpA

PFOA

© Copyright ARCADIS 2015

PFOS AA-EQS is extremely low / very conservative 0.65 ng/L3 orders of magnitude lower than drinking water standards.

EU Environmental Quality StandardsSurface Waters

• Directive on “Environmental Quality Standards” EQSD 2008/105/EC, daughter directive of the Water Framework Directive: Standards for priority hazardous substances. Review each 6 years. In 2013, PFOS was added as a priority hazardous substance / EQS derived by RIVM (NL).

• Member State Legislation: November 2015. The EQS shall be met by End of 2027.

Name of

substance

Annual Average-EQS

(µg/L)

Max. Allowable Con.

EQS (µg/L)

EQS

(µg/kg)

Inland

surface

waters

Other

surface

waters

Inland

surface

waters

Other

surface

waters

Biota

Perfluoro octane

sulfonic acid and

its derivatives

(PFOS)

0.00065 0.00013 36 7.2 9.1


Analytical Challenges

• AFFF contained many thousands of PFAS compounds including precursors

• Current analytical methods only examine a small fraction of the compounds present (16 - 39 compounds)

• Microbes the attack the non perfluorinated parts of the PFAS precursor molecules making perfluorinatedcompunds as dead end daughter products

• So precursors biotransform to make perfluorinatedcompounds which do not biotransform further and are non-biodegradable

• There are potentially hundreds of PFAS compounds to assess (C2 –C16, straight chain, branched chain, cyclic, telomers, betaines, sulphonamide, amino etc.)

• The analytical costs to assess the concentration of all of these PFAS individually will be substantial

© Arcadis 2015

Advanced Analytical TechniquesExpanding analytical tool box to deal with precursors and cost

New analytical tools applied but not yet proven to be comprehensive..

4 July 2016Useful Graphics 35

LCMSMS

• Most common tool is LCMSMS –Liquid Chromatography with tandem mass spectrometers (US EPA 537)

• Can detects C4 to C12 perfluorinated carboxylates (PFCAs) & sulphonates (PFSAs) (including PFOS & PFOA)

• Detection limits to approx. 0.09 ng/L

Total Oxidisable Precursors (TOP) Assay

• Pre-treatment of samples using conventional chemical oxidation which converts precursors to perfluorinated carboxylates (PFCAs) & sulphonates (PFSAs) which can be detected using by LCMSMS;

• Shows sum of precursors which are converted to PFCA’s & PFSA’s - Done in addition to LCMSMS to provide difference between precursor and free PFCA & PFSA concentrations

• Detection limits similar to LCMSMS to approx. 2 ng/L

Particle Induced Gamma Emmission (PIGE) Spectroscopy• Separation of organofluorine compounds by SPE cartridge then analysis of total fluorine content to give a sum of

fluorinated species (analogous to TPH for hydrocarbons)

• Detection limits to 2.2 ug/L F

Adsorbable Organo Fluorine (AOF)• Separation of organofluorines by synthetic Activated Carbon (AC) & subsequent analysis by hydropyrolysis

combustion ion chromatography (CIC) – sum organofluorine (analogous to TPH for hydrocarbons)

• Detection limits 1 ug/L F

© Arcadis 2015

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

Too many PFAS compounds and precursors –so very expensive analysis

This analytical method convert PFAA precursors to PFAA’s

Termed Total Oxidiseable Precursor (TOP) Assay

[email protected]

mailto:[email protected]


0

2,500

5,000

7,500

10,000

Soil Composite Pre-TOP Assay(Average of

Duplicate Data)

Soil CompositePost-TOP Assay

(Average ofDuplicate Data)

Concentr

ation (

µg/k

g)

PFNA (C9)

PFOA (C8)

PFHpA (C7)

PFHxA (C6)

PFPA (C5)

PFBA (C4)

PFOS (C8)

PFHpS (C7)

PFHxS (C6)

PFBS (C4) 0

50

100

150

GroundwaterComposite Pre-TOP

Assay(Average of

Duplicate Data)

GroundwaterComposite Post-TOP

Assay(Average of

Duplicate Data)

Concentr

ation (

µg/l)

PFNA (C9)

PFOA (C8)

PFHpA (C7)

PFHxA (C6)

PFPA (C5)

PFBA (C4)

PFOS (C8)

PFHxS (C6)

PFBS (C4)

Total Oxidisable Precursor (TOP) Assay

• Significant increases in perfluorinated carboxylic acids and sulphonic acids (PFAAs) following TOP assay reveal the hidden mass of PFAA precursors present

– An additional 240% of PFAS in soils and 75% in groundwater

• Demonstrates matrices impacted with AFFF contain a greater mass of PFAS than identified by conventional analysis with LC-MS/MS (EPA Method 537).

Soil Composite Groundwater Composite

240%

increase75%

increase


TOP Assay

• Majority of PFAAs identified following TOP assay comprised C4 to C8 carboxylic and sulphonic acids;

• TOP assay generated 3 order of magnitude increase in soil PFHxA (4.6ug/L to 975ug/L)

0%

10000%

20000%

30000%

PFBS(C4)

PFHxS(C6)

PFHpS(C7)

PFOS(C8)

PFBA(C4)

PFPA(C5)

PFHxA(C6)

PFHpA(C7)

PFOA(C8)

PFNA(C9)

PFDA(C10)

PFUnA(C11)

PFDoA(C12)

6:2 FtS(C8)

% Increase in PFAS Compounds Following TOP Assay in an AFFF-Impacted Soil

© Arcadis 2015

PFAS Measurement in Groundwater with TOP Assay

Only 28% (86 µg/L PFAS) was

measured using standard analytical methods.

Post-TOP assay sample results represent 100% of measurable PFAS

Total PFAS Measured in Pre-TOPAssay Sample

Additional PFAS Measured inPost-TOP Assay Sample

An additional 216 µg/L PFAS was

measured following TOP Assay

© Arcadis 2015

Method Comparison:TOP Assay vs AOF

y = 0.7791x + 1.7479R² = 0.7702

0

10

20

30

40

50

0 10 20 30 40 50

AO

F µ

g/L

(o

rgan

ofl

uo

rin

e)

LC-MS/MS post TOP Sum PFAS (organofluorine equivalent)

© Arcadis 2015

Conceptual Site Model

• Source zone – hidden cationic & cation dominated zwitterion “Dark Matter” in more anaerobic environment

• Mobile zone – hidden anionic & anion dominated zwitterions (more mobile) PFAA precursors, “Dark Matter”

• Anionic precursor biotransformation increases as aerobic conditions develop in the downgradient of hydrocarbon plume

• Increasing mobility of shorter perfluoroalkyl chain PFAS

© Arcadis 2015

P&T with GAC treatment is the most commonly applied technology –less effective on shorter chain PFAS

PFAS Groundwater Remediation• Currently proven commercial option is P&T for C8 compounds

• GAC can be effective in removing PFOS/PFOA, however

sorption is low and competition occurs (much higher costs than

for conventional contaminants)

• GAC increasingly less effective as PFAS chain length

diminishes

• Ion exchange resins or polymers with a large surface area may

be suitable for low concentrations and high volumes,

• Other potential techniques are nano filtration and reverse

osmosis

• Oxidation via conventional methods is difficult due to strength of

the C-F bond and may lead to higher PFCA / PFSA levels as a

result of precursor breakdown using oxidants

• Arcadis ScisoR shown to defluorinate PFOS with in situ treatment

planned for 2016

© Arcadis 2015

PFAS Soil Remediation• Currently options are limited to excavation,

stabilization or capping

• Landfilling introduces challenges since PFAS will

become constituents of leachate (landfill leachate

is not typically being evaluated for e.g. PFOS)

• Incineration, high temperatures (> 1,100 °C) are

needed to cleave the stable C-F-bonds

• Immobilization with GAC or commercial products

(soil mixing) e.g. Rembind.

• Solidification (e.g. cement) is a yet unproven long-

term option

• Arcadis ScisoR trials on soil mixing progressing

Soil remediation largely relies on excavation/stabilization/ immobilization and not destruction


Cost of PFOS Groundwater Treatment with GAC

Low sorption of PFCs → higher GAC consumption, cost

At influent concentrations 3 to 20 µg/L; effluent 0.1 µg/L:

Parameter Charge capacity

(% wt)

Annual GAC Costs ($/Year)

75 Lpm 166 Lpm 832 Lpm 1,665 Lpm

PFOS 0.002 to 0.005 3,932 7,865 39,322 78,643

Chlorinated

hydrocarbons

0.02 to 0.4 256 512 2,555 5,112

BTEX 0.1 to 2.0 52 102 512 1,022

PAH 1.3 to 2.5 29 57 284 568


PFAS Remediation

© Arcadis 2015

0

10000

20000

30000

40000

50000

60000

Blanco SC1-1 SC1-2 SC1-3 SC1-4 SC1-5

H4PFOS

C7A

C7S

C8A

C4S

C5A

C4A

C6A

C6S

C8S

Oxidation Results: peroxide activated persulfateSoil and Groundwater

Conventional ISCO creates PFAA’s from precursors

Co

ncen

tra

tio

n (

ng/L

)

H4PFOSC7A

C7SC8A

C4SC5A

C4AC6A

C6SC8S

0

5000

10000

15000

20000

25000

30000

35000

Blanco SC2-1 SC2-2 SC2-3 SC2-4

H4PFOS

C7A

C7S

C8A

C4S

C5A

C4A

C6A

C6S

C8S

• 300 g soil, 300 mL groundwater

• PFAS monitored in reactor supernatant

© Arcadis 2015

H4PFOSC7A

C7SC8A

C4SC5A

C4AC6A

C6SC8S

0

5000

10000

15000

20000

25000

30000

35000

Blanco SC2-1 SC2-2 SC2-3 SC2-4

H4PFOS

C7A

C7S

C8A

C4S

C5A

C4A

C6A

C6S

C8S

Oxidation Results: ScisoR®

Soil and Groundwater

• Destruction of PFAS and PFAA’s in soil and groundwater by chemical oxidation / reduction using ScisoR®

• Effective at ambient temperature

• Reagents can be injected or mixed with impacted soil and groundwater

• In Situ remediation of PFAS impacted source areas enabled

• Could be used to regenerate sorbent media (e.g. GAC, ion exchange resins)

• Patent granted in NL. Provisional patent in the US. Patent Cooperation Treaty (PCT) procedure pending for worldwide patent rights

Conventional ISCO creates PFAA’s from precursors

ScisoR destroys PFAA’s and precursors

• 300 g soil, 300 mL groundwater

• PFAS monitored in reactor supernatant


0%

20%

40%

60%

80%

100%

120%

Average % PFOSRemaining

Post ScisoR®

PFOS Destruction during ScisoR®

0%

20%

40%

60%

80%

100%

120%

Average % FluorideReleased from

PFOSPost ScisoR®

Fluoride Released from PFOS

during ScisoR®

PFOS Destruction & Fluoride Mass Balance During ScisoR®

• 10 mg/L PFOS starting concentration

• 3 replicate data sets

• 83 to 90% PFOS destruction after 14 days

• 71% to 118% fluoride released from PFOS during SCISOR

• Overall fluoride mass balance (remaining fluoride in PFOS + fluoride released to solution)

− 86% to 126% of theoretical

• All treated samples were blind spiked with 10 mg/L fluoride

− 80% to 99% spike recovery

• Spike analyses demonstrate ion measured is fluoride, results are quantitative

• Longer reaction times and repeat applications of ScisoR will cause complete destruction of PFOS

4 July 2016 51Replicate Data. Error bars are % Standard Error of Measurement (SEM)


Environment Canada -ScisoRPFOA as transformation product of PFOS

water spiked with 100 µg L-1 PFOS


ScisoR Field Demonstrators

• ScisoR Ex Situ On Site Remediation of Unsaturated Soils

• ScisoR In Situ Aquifer Remediation

1. Europe, June 2016 – site work

2. UK, April 2016 – lab

3. North America 2016 – repeat lab with TOP

4. Australia, May 2016 – lab

© Arcadis 2015

PFAS -Manage your risks

• PFAS are highly mobile in groundwater, persistent and toxic

• PFAS sources can comprise fire training areas FTA’s

• Identifying if certain FTA’s are located in environmentally sensitive locations will potentially establish if harm is being caused

• Risk ranking a portfolio of FTA’s is a first logical step to manage potential risk

• Arcadis is working for multiple clients on portfolios of PFAS impacted sites using risk based tools to manage potential risks to multiple receptors from use of PFAS

https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos

US EPA has established the drinking water health advisory

levels at 70 parts per trillion (ng/L) 19th May 2016

https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos

© Arcadis 2015

• PFAS do not biodegrade (mineralise) but biotransform to PFAAs as dead-end daughter

products

• Regulations surrounding PFAS are evolving with lowering drinking water standards and a

focus on increased interest in additional PFAAs

• Significant PFAA precursor mass (“Dark Matter”) and multiple PFAAs likely accompany

PFOS & PFOA in sources and plumes –depending on exact nature of source material

• Analysis of just PFAA’s may significantly underrepresent the actual PFAS mass

• Methods to determine the sum PFAS mass are available commercially via ARCADIS and

show good initial correlation

• TOP Assay correlates well with AOF; TOP Assay appears more comprehensive

• A CSM is proposed based on TOP, AOF and PIGE data from an FTA source and plume

• ScisoR has been demonstrated to mineralise PFOS

• Arcadis is moving to field scale application of ScisoR for on site / in situ destruction of

PFAS on 3 continents

Summary

© Arcadis 2015

Contacts

Ian Ross Ph.D.Global PFAS LeadArcadis [email protected]

Jeff BurdickNorth America PFAS LeadArcadis [email protected]

Tessa PancrasEuropean PFAS LeadArcadis [email protected]

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




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

poly- and perfluoroalkyl substances (pfas)... · poly- and perfluoroalkyl substances (pfas) big...

Documents