PFAS SITE CHARACTERIZATION TECHNIQUES

PFAS SITE CHARACTERIZATION TECHNIQUES Erica Kalve, Dr. Erika Houtz, Jeff McDonough, and Dr. Ian Ross

September 26, 2018

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Presentation Overview• Background Information

• Regulatory Setting

• Conceptual Site Models for PFAS

• PFAS Site Investigation Considerations

• Case Study

• Questions

16 October 2018 2© Arcadis 2017Property of Arcadis, all rights reserved

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What are PFASs

16 October 2018 3

PFASs comprises many thousands of compounds –multiple sources

PFASs are impacting drinking water worldwide

Some PFASs 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

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Potential Primary Sources of PFASs

Secondary sources include stormwater outfalls, WWTP, landfills, biosolids, etc. 16 October 2018 4

AFFF Metal Coating

Performance Plastics Electronics Textiles Paper &

Packaging

Paints Hydraulic Fluids

Personal Care

ProductsPhoto

ProcessingBuilding Materials

Insecticide/Herbicide


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Per- and Polyfluoroalkyl Substances (PFASs) (>3,000 compounds)

Perfluorinated Compounds (PFCs) akaPerfluoroalkyl Acids (PFAAs)~25 common individual compoundsbut ~100’s compoundsPFOS ,PFOA, PFHxS, PFBA, GenX

Polyfluorinated compounds (~3,000 compounds)

Microbial / Higher Organism BiotransformationMore Commonly

Regulated

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Perfluoroalkyl group –the forever functional group

PFOA

PFOS

PFHxS


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Polyfluorinated/PFAA

precursors in commerce

Hundreds of intermediate

transformation products

Approximately 25 PFAA

(PFSA, PFCA, PFPA)

Fire Training Areas

LandfillsBiosolids Land

Application

Manufacturers of Products

1,000s of polyfluorinated

precursors

Approximately 25 perfluorinated compounds

that can be detected


716 October 2018

Aerobic Biotransformation Funnel

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PFOS/PFOA in US Public Water Supplies• US EPA UCMR3 sampling of

public drinking water conducted from 2013 through 2015. Included 6 PFASs.

• In May 2016, US EPA announced a drinking water health advisory limit (HAL) for PFOS and PFOA (separately or combined) at 70 ppt (ng/L).

• Updated evaluation of UCMR3 data meant 60 water supplies were above HALs and 6 million Americans were affected

16 October 2018 8

Data source: USEPA Unregulated Contaminant Monitoring Rule 3 (2013 – 2015), available at https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule.


https://www.epa.gov/dwucmr/occurrence-data-unregulated-contaminant-monitoring-rule

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Evolving Regulatory PFAS Values – Overview

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Drinking, Surface and Ground Water (µg/l)

PFOS O=8PFOA O=8PFBS B=4PFBA B=4

PFPeA/S Pe=5PFHxA Hx=6

DENMARK(Drinking & Groundwater)

FEDERALGERMANY

(Drinking Water)

(0.1)

UK(Drinking Water)

AUSTRALIA(Drinking Water)

(0.09)

THE NETHERLANDSUS EPA(Drinking Water)

VERMONT(Drinking Water)

MINNESOTA(Drinking Water)

NEW JERSEY

CANADA(Drinking Water)

PFHxS Hx=6PFHpA Hp=7PFOSA O=8

PFNA N=9PFDA 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/

.030.50.5

(0.1)

0.3

0.60.2

15

300.20.2

0.2

0.2

.014.013

(0.02)

.027.035

77

0.560.29

3471

.093.093

0.56

0.290.37

.093

0.6

.53.023ground

drinking

0.5

drinkingdrinking.01ground

0.29

SWEDEN(Drinking Water)

(0.5)(0.5)(0.5)(0.5)

(0.5)(0.5)

0.3

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)

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Relevant guideline and regulatory limits are not limited by laboratory detection limits.10

All concentrations provided as µg/L; values in parentheses are a summationDrinking Water Values PFOS PFOA PFBS PFBA PFHpA PFNA PFHxS

Minnesota 0.027 0.035 7 7 - - -New Jersey 0.013 0.014 - - - 0.013 -

Vermont (0.02) (0.02)

Pennsylvania 0.005U.S. EPA, and many states (0.07) (0.07) - - - - -Groundwater Values PFOS PFOA PFBS PFBA PFHpA PFNA PFHxS

Alaska 0.4 0.4Connecticut (0.07) (0.07) (0.07) (0.07) (0.07)Michigan (groundwater surface water interface) 0.012 12

New Jersey - - - - - 0.01 -New Hampshire (0.07) (0.07)Texas, Residential 0.56 0.29 34 71 0.56 0.29 0.093


Sample of US Guidance Values

PFOA and PFOSPROPERTIES AND CHEMISTRY

Chemical Properties

PCB (Arochlor

1260)PFOA PFOS TCE Benzene

Molecular Weight 357.7 414 500 131.5 78.11Solubility (@20-

25°C), mg/L 0.0027 3,400 – 9,500 519 1,100 1,780

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

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PFOA/PFOS plumes can be longer than other contaminant plumes.16 October 2018 12

0 1 2 3 4 5 6

PFAAs

CVOCs

MTBE

BTEX

PCBs

Plume Length (mi)

Large diffuse plumes, often times orders of magnitude above Health Advisory Levels (HALs)


Nature and Extent Considerations

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• Hydrophobic interaction

• Predominant sorption mechanism for long chain PFAS• Organic rich soils retard movement of PFAS• foc increases -> Kd increases• Oil and other organics may also increase sorption

• Electrostatic effects

• Positively charged PFAS (i.e. some precursors) sorb to negatively charged minerals

• Negatively charged PFAS sorb to positively charged minerals• Under acidic pH, mineral surfaces tend to be more positively charge –

promoting adsorption of PFAAs• Electrostatic repulsion can decrease PFAS sorption• High ionic strength dulls electrostatic repulsion; favoring adsorption

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Chuyang Y. Tang, Q. Shiang Fu, Dawen Fao, Craig S. Criddle, and James O. Leckie. Effect of solution chemistry on the adsorption of perfluorooctane sulfonate onto mineral surfaces. Water Reasearch 44 (2010) 2654-2662.

Conceptual hydrophobic interaction

Conceptual electrostatic effects

Conceptual repulsion

Subsurface retardation of PFOS in Groundwater

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Polyfluorinated Compounds - PrecursorsVolatile

-

Relatively mobile in groundwater

6:2 fluorotelomer sulfonate

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16 October 2018

Fluorotelomer alcohol, 8:2 FTOH

Fluorotelomer Thiohydroxy Ammonium

Likely to sorb strongly to negatively- charged soils

Telomers biotransform to PFCAs

Perfluoroalkyl Sulfonamide Amino Carboxylate

Multiple charges – transport behavior more difficult to predict

Sulfonamides biotransform to

PFSAs

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Increasing mobility of shorter perfluoroalkyl chain PFAS

C6 C4 C5 C3? C2?

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

Anionic precursor biotransformation increases as aerobic conditions develop

Direction of groundwater flow

Anionic PFAAdead enddaughters

0

0

C F S 08 17

00

0H3C 0C 4H9

0

C8F17 S 0 0

00

0H3C 0C 4H9

0

0

S 0C8F17

C F

0

0

S 08 17

0

0

C6F13

S 0

0

0

C8F17

0

0

S 0S 0 C8F17

0

0

S 0C8F17

0

S 0C8F17

0

0

S 0C 6F13

0

C 6F13

0

0

0

S 0S 00

C6

F13

Source Zone - Hidden Cationic and Zwitterionic PrecursorsLess 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

00

C1H9

C F

H3C 0

0

0

S 08 17

0

0

SN HC 8F17

NH +

FF C

n

0

0 0H

NS

F

F C

F n0

0

H3C 00 C 4H9

0

0H

0

N+F

FF C

F

C6F13

0

0

S 0 N

NNS

0 H

0

F

F C

F n

0

0-C5F11

0

H3C 0

00

0H3C 0C 4H9

0 C4H9

0 0

C6F17 S 0

0

CH

CH

CH

CHCH

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

C7C8

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PFAS Source Zone CSM

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C8 Transport

C6 Transport

leaking sewer lateral

Wastewater Treatment FacilityFire Training Area Discharge to Surface WaterC8/PFOS-Based Foam Use C6 PFAS-Based Foam Use

C8 partially removed from aqueous streamC6 minimally removed (if at all)

Diffuse C8 and relatively higher concentration of C6 PFASs present

Downgradient Water Supply Wells

Potable UseC8/PFOS regulated at ng/LC6 regulated at µg/L

C6 and short-chain PFASs bioaccumulation*

Non-Potable Use

*Identified in edible portion of some crops (fruit)Property of Arcadis, all rights reserved

Fate and Transport Consideration

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PFAS Site Characterizations, Pre-Field Considerations

Err on the side of caution - low DLs and potential PFAS cross-contamination!16 October 2018 17

Confirm desired analyte list with client and lab

Research materials

compatibility

If soil sampling, discuss soil

homogenization


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Key Sampling Procedure Guidance Documents

16 October 2018 18

Department of Environment Regulation, Government of Western Australia: Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS). Contaminated Sites Guidelines. February 2016.

United States Army Corps of Engineers. Standard Operating Procedure 047: Per/Poly Fluorinated Alkyl Substances (PFAS) Field Sampling. Revision: 1. March 2016.

New Hampshire Department of Environmental Services. Perfluorinated Compound (PFC) Sample Collection Guidance. November 2016.

Massachusetts Department of Environmental Protection. DRAFT Fact Sheet, Guidance on Sampling and Analysis for PFAS at Disposal Sites Regulated under the Massachusetts Contingency Plan. January 2017.


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Acceptable Sampling Materials

Plan to pre-test the source water prior to investigation!16 October 2018 19

Water Sampling

HDPE and silicone tubing

and bailers

HDPE Hydrasleeves™

Drilling and Soil Sampling

PFAS-free makeup water

PFAS-free drilling fluids

Acetate liners

Sample Containers and

Storage

HDPE sample containers with HDPE lined lids

for soil and water samples

Ice contained in plastic

(polyethylene) bags (double

bagged)

Field Documentation

Sharpie®

Ball point pens

Standard paper and paper

labels

Decontamination

Alconox®, Liquinox® or

Citranox®

Methanol, isopropanol, or

acetone

PFAS-free Water


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Restricted Sampling Materials

Review all aspects of equipment and materials (e.g., o-rings, ball valves, etc.)!16 October 2018 20

Water Sampling

Teflon® or PTFE containing tubing and

bailers

LDPE Hydrasleeves™

Passive Diffusion Bags

Water particle filters

Drilling and Soil Sampling

Aluminum foil

Drilling fluid containing PFASs

Sample Containers and

Storage

Glass sample containers with lined

lids

LDPE containers and lined lids

Teflon® or PTFE-lined lids on containers

Reusable chemical or gel ice packs (e.g.

BlueIce®)

Field Documentation

Self-sticking notes and similar products

Waterproof paper, notebooks, and labels

Non-Sharpie® markers

Decontamination

[Some] detergents and decontamination

solutions (e.g., Decon 90®

Decontamination Solution)


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Personal Care Products Personal Protective Equipment

Food Packaging Rain Events

Common Sense

Other Considerations

Health and safety must come first!16 October 2018 21


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• USEPA 537 is a drinking water method, modifications for soil and groundwater are based on laboratory specific protocols

• QSM 5.1 (recently updated to 5.1.1) aligns standard operating procedures for non-drinking water sample matrices

• Trip blanks are used for quality control sampling of volatile compounds – most PFASs of interest are not volatile

• Best practices for quality control sampling during PFAS site investigation:

• Daily collection of equipment blanks using laboratory-supplied “PFAS-free” water• Field reagent blanks • Field duplicates and matrix spike samples

Quality Control Considerations

Following best practices, water samples should be analyzed using whole sample analysis – therefore, the lab cannot reanalyze if needed…

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Smart Characterization

It’s not just about more data, it’s what you do with the data that counts!16 October 2018 23


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Modified USEPA 537

Water and Soil

Direct inject or SPE cleanup/concentration

Matching labelled internal standards and surrogates

Single digit ppt detection limits

20 to 30 minute turnaround times

20-30 samples per day throughput

Plan is to be DoD QSM v 5.1 Compliant

Provides benefits of real-time adaptive characterizationProperty of Arcadis, all rights reserved

Cascade’s PFAS MobiLab

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• Former plating line removed in the 1980s.• Precipitation infiltrates concrete creating a

“bathtub” effect in the former plating line backfill.

• PFAS impacted water drains into permeable stringers throughout a perched aquifer.

• Bedrock drinking water supply; within a well protection area.

• Plume migration driven by precipitation recharge and radial flow creates a multi-lobed plume that is highly variable and seasonally influenced.

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High Resolution Site Characterization Using MobiLab: Case Study August 2017


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Dry boring

Perched PFAS Delineation

PFOS is the primary compound of concern

• PFOA and other PFAS coincident with elevated PFOS but at lower concentrations

PFOS requires additional delineation off-site to east

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Completed an adaptive investigation using Cascade’s mobile laboratory• 35 borings / 25 GW samples

• Split five samples for fixed laboratory comparison (both extracts and groundwater)

PFOS < 12 ng/LPFOS > 12 ng/LPFOS > 70 ng/L

PFOS > 12 ng/L PFOS > 70 ng/L


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• Good agreement between split samples (5) analyzed by mobile lab and fixed lab (Eurofins).• Consistent data for both low and high concentration samples.• Analyzed for 9 PFAS compounds with good agreement.

Mobile Analytical Data Comparison with Fixed Laboratory


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Erica KalvePrincipal GeologistEmerging Contaminants Focus Group Lead

o 415 915 8052c 510 206 4514e [email protected]

Questions

16 October 2018 28

mailto:[email protected]

PFAS SITE CHARACTERIZATION TECHNIQUESErica Kalve, Erika Houtz, Jeff McDonough, and Ian Ross| March 21, 2018

© Arcadis 2017

Take Home Messages Background Information

PFASs are a large family of compounds. Broad spectrum of uses in every day

materials and potential point source areas No biodegradation at all, just

biotransformation UCMR3 results indicate that ~2% of large

public water supplies contain unsafe levels of PFOS/PFOA

Regulatory Setting Global regulations and awareness PFOS/PFOA have combined USEPA Health

Advisory Level (HAL) of 70 ppt Many State-specific guidance values

Fate and Transport CSM They move fast in groundwater (shorter

chains faster than longer chains) Attenuation via hydrophopbic and

electrostatic mechanisms

PFAS Site Investigation Strategies For the most part, standard sampling

techniques are acceptable for PFASs Materials compatibility is the major concern

with PFAS sampling plans Save money on trip blanks and use your

budget to evaluate other QC samples The PFAS MobiLab by Cascade is a great

tool for adaptive investigation and flux-based site characterization