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PFAS SITE CHARACTERIZATION TECHNIQUES Erica Kalve, Dr. Erika Houtz, Jeff McDonough, and Dr. Ian Ross
September 26, 2018
© Arcadis 2017
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
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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.
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Evolving Regulatory PFAS Values – Overview
9
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
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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)
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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
13
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.
25
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
26
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 erica.kalve@arcadis.com
Questions
16 October 2018 28
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