INTRODUCTION TO PFAS November 8, 2019
trcsolutions.com | PFAS in the News https://pfasproject.com
trcsolutions.com 2 Today’s Topics
• PFAS Naming Conventions
• Physical/Chemical Properties of PFAS
• Sources of PFAS and Potentially- affected Sites
• Replacement PFAS Chemistry
• AFFF
• Toxicology
3 PFAS Naming Conventions
4 Acronyms
• PFC = Per-fluorinated chemical PFCA • PFAS = Per- and Poly-fluoroalkyl substances Perfluoroalkyl Substances PFAA
• PFAA = Perfluoroalkyl acids PFSA • PFOA = Perfluorooctanoic acid (perfluorooctanoate)
• PFOS = Perfluorooctane sulfonic acid (perfluorooctane sulfonate)
• PFCA = Perfluorocarboxylic acids
• PFSA = Perfluorosulfonic acids trcsolutions.com 5 Perfluorinated Compounds (PFCs)
PFCs: Do not use this acronym anymore!
• PFCs previously used to describe greenhouse gases
• PFCs do not include polyfluorinated compounds
6 Quick Chemistry Lesson #1 • Remember: PFAS are Per and Polyfluoroalkyl substances • Per-fluoroalkyl substances: fully fluorinated alkyl tail • Perfluoroalkane carboxylates (or carboxylic acids): PFCAs
FFF F F F O COOH = Head F C C C C (PFOA) C C C C OH F PFAAs F FFFFFF Alkyl tail, fully fluorinated
• Perfluoroalkane sulfonates (or sulfonic acids): PFSAs
FFF F F F F F
F C C C C (PFOS) C C C C SO3H SO3H= Head F
F FFFFFF 7 Quick Chemistry Lesson #2
• Remember: PFAS are Per and Polyfluoroalkyl substances
• Poly-fluoroalkyl substances: non-fluorine atom (typically hydrogen or oxygen) attached to at least one carbon atom in the alkane chain
Fluorotelomer Alcohol (8:2 FTOH)
FFF F F F F F HH C C C C C C C C C C OH F FFFFFFFFHH
Non-fluorine atom on one or more carbons.
Polyfluoroalkyl substances may also be degraded to perfluoroalkyl substances (e.g., PFOS or PFOA): PRECURSORS 8 Nomenclature • Remember: PFAS are Per and Polyfluoroalkyl substances • Per-fluoroalkyl substances: fully fluorinated alkyl tail
Acronym Compound Name Carbon Chain Length PFOA Perfluorooctanoic acid C8 PFOS Perfluorooctanesulfonic acid C8 PFBA Perfluorobutanoic acid C4 PFBS Perfluorobutane sulfonic acid C4 PFHxA Perfluorohexanoic acid C6 PFHxS Perfluorohexane sulfonic acid C6 • Poly-fluoroalkyl substances: partially fluorinated alkyl tail
‒ Fluorotelomers
TRCcompanies.com Polyfluoroalkyl substances can also be precursors. 9 Summary of PFAS Families
PFAS
Non-polymer Polymer Potential Precursors
Perfluorinated Polyfluorinated Precursors
PFAAs FTSAs PFCAs FTCAs FTOHs PFSAs FASEs FASAs FASAAs trcsolutions.com 10 What is a Precursor? FTSAs: . Stable under anoxic conditions . Likely degrade to PFCAs in aerobic surface waters
• Polyfluoroalkyl substances transformed to PFAAs
• Transformation
• Precursors are a concern
• 1000s of these
trcsolutions.com 11 PFAS Families
PFCA Fluorotelomer-based Substances FOSE ECF-based PFAA FTOH FTSA FTCA Substances PFSA FOSAA
• FOSE: raw material in ECF • Directly released to • From telomerization process process environment • Can biotransform into PFCAs • FOSAA: degradation • Produced by precursor intermediate degradation • FTOH far more volatile • Can biotransform into PFCAs and PFSAs
trcsolutions.com 12 Polyfluorinated Substances Producing PFAAs
13 PFOS: Linear and Branched Isomers
Linear Isomers 3M AFFF: Branched and linear isomers (30:70) If exclude branched isomers, concentrations underestimated and biased low. Branched Isomers
trcsolutions.com 14 PFOS: Linear and Branched Isomers
trcsolutions.com 15 PFOA: Branched and Linear Isomers: Lab Quantitation
Correct integration of PFOA Incorrect integration of PFOA
trcsolutions.com 16 Long Chain Versus Short Chain Why does it matter? • Short chain: • Long chain: – PFCAs with seven or fewer carbons – PFCAs with 8 or more carbons – PFSAs with five carbons or less – PFSAs with six or more carbons
Perfluorohexanoic acid (PFHxA) is short chain PFCA. Perfluorohexane sulfonic acid (PFHxS) is long chain PFSA.
Short-chain PFCAs Long-chain PFCAs
PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA
PFBS PFPeS PFHxS PFHpS PFOS PFNS PFDS PFUnS PFDoS
Short-chain PFSAs Long-chain PFSAs trcsolutions.com Source: March 2018 ITRC Factsheet 17 What Are PFAS?
• Poly- and per-fluoroalkyl substances ─ Generic family of chemicals ─ Manmade and do not occur naturally ─ Used since 1940 (Critical for the Manhattan Project) ─ Can be branched or linear ─ Used to make products that resist heat, oils, grease, stains, and water • Most prevalent and researched: PFOA and PFOS • PFAS: Acid or anion? PFOS is present in the environment in the anionic form: perfluorooctane sulfonate.
Perfluorobutanoic acid Perfluorobutanoate (+ dissociated proton) trcsolutions.com 18 CAS Numbers and PFAS State
PFAS State Structure CAS No.
- Anion Perfluorooctanoate C7F15CO2 45285-51-6 PFOA Acid Perfluorooctanoic acid C7F15COOH 335-67-1
- Anion Perfluorooctane sulfonate C8F17SO3 45298-90-6 PFOS
Acid Perfluorooctane sulfonic acid C8F17SO3H 1763-23-1
trcsolutions.com Why is this important? 19 Chemical Properties of Perfluoroalkyl Substances A PFAS Micelle • C-F: Strong bond
• Chemically and thermally stable
• Water soluble and mobile in groundwater
• Surfactant properties
• Recalcitrant in environment
trcsolutions.com 20 Properties: Acid vs Cation vs Anion Form
PROPERTY AVAILABILITY • Physical description • White powder or waxy substance • Molecular weight • Known • Solubility in water • Known for acid and cation; N/A for Anion • Vapor Pressure • Known for acid; N/A for anion and cation (*) • Henry’s Law constant • Estimated for acid; N/A for anion and cation (*) • Kow • Typically see values for acid form • pKa • Half-life • Generally not available (some modeled values available) • BCF and/or BAF • Known for anion; N/A for acid & cation
trcsolutions.com 21 Sources of PFAS and Potentially Affected Sites
trcsolutions.com 22 Where Are PFAS Used?
trcsolutions.com 23 What Types of Sites Can Be Sources of PFAS?
• Fire training facilities • Fire stations • Refineries • DoD sites/Military bases • Commercial and private airports • Landfills (leaching from consumer products) • Biosolids land application • Rail yards • Chemical facilities • Plating facilities • Textile/carpet manufacturers • Residential areas with septic systems trcsolutions.com 24 Timeline of PFAS
1938 1949 1956 1968 1978
•PTFE •PTFE used in • Stain-resistant •Navy •Detected in discovered products products developed blood of (PFOS) AFFF manufacturing workers
2016 2002 2006 2009 2013-2015 •EPA Health •PFOS • PFOA phased out •Stockholm • PFOA phase-out Advisory manufacturing •EPA PFOA Convention complete announced for phased out Stewardship classifies PFOA/PFOS Program PFOS as POP • Sampling of public (70 ppt) drinking water wells for PFAAs (UCMR3)
trcsolutions.com 25 Global Manufacture and Use of PFAS Banned Sale, Prohibits Import, Use and Import Manufacture, of PFOA: Use & Sale of PFOS/PFOA: European Union Canada
Restrict Manufacture, PFOA & PFOS No Import, Export, and Use of Longer PFOS: Japan Produced: US, Increased Europe, Japan Production of PFOA: China, India, EtFOSA Produced on Industrial Scale: Brazil Russia Class B AFFF with PFAS Banned: PFAS Manufactured Globally South Australia trcsolutions.com 26 Replacement Chemistry
• GenX replaces PFOA
• ADONA replaces PFOA
• 6:2 Fluorotelomers replace PFOS in metals plating
• Telomers replace PFOS and PFHxS in AFFF
• Shorter chain PFAAs replace PFOA: PFBA, PFPeA trcsolutions.com 27 Four New PFAS in Revised EPA 537 Method
Analyte Acronym CAS Number
Hexafluoropropylene oxide dimer acid HFPO-DA 13252-13-6
11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid 11Cl-PF3OUdS 763051-92-9
9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid * 9Cl-PF3ONS 756426-58-1
4,8-dioxa-3H-perfluorononanoic acid * ADONA 919005-14-4
*F53B compounds
All new compounds have an oxygen molecule in the carbon chain.
28 Hexafluoropropylene oxide dimer acid (HFPO-DA)
• Perfluoroether carboxylate surfactant
• Dupont/Chemours
• Is not Gen-X – one component of the Gen-X processing aid technology – is a Gen-X chemical
• Shorter-chain PFAS: 6 carbons; 5 fluorinated
• Replacement for PFOA as a surfactant and polymerization aid in production of PTFE product
29 ADONA
• Polyfluoroether carboxylate surfactant
• 3M/Dyneon ADONA • Shorter-chain PFAS (7 carbons; 6 are fluorinated)
• Replacement for PFOA as a polymerization aid in production of PTFE product
30 F-53B
• Chlorinated polyfluorinated ether sulfonate • Used in metal plating as alternatives to PFOS for mist suppression • F-53 salts likely derived from fluorotelomer raw material • Used as mist suppressant in chrome plating industry for over 30 years in China • F-53 vs F-53B
11Cl-PF3OUdS 9Cl-PF3ONS F53B: minor component F-53B: major component
31 Aqueous Film Forming Foam (AFFF)
trcsolutions.com What is AFFF? • Highly effective fire-fighting foam • Used for hydrocarbon fuel fires • AFFF acts as: – An aqueous foam: primary fire extinguishing agent – An aqueous film former: a fuel vapor suppressor
TRCcompanies.com 33 Where is AFFF Used? • Airports (military/domestic)
• Petrochemical Facilities
• Municipal Fire Dept.
• Industrial Fixed Systems
• Military / Government
• Marine – Off Shore Fire Protection
• Where: – Historical Use (where used to fight a fire) – Fire Training Areas – Nozzle Testing Areas –Storage Areas TRCcompanies.com 34 Types of Fluorine-Based AFFF
nd Modern Legacy 1st 2 Generation Fluorotelomer & Fluorotelomer Generation AFFF Precursors AFFF AFFF
. PFOS based (80%) . Sold from 1970s - 2016 . Most foam mfrs transitioned to this . Telomer based (20%) . Telomers . No PFOS and no . Developed in 1960s . PFOR compounds (R= cationic and anionic heads) breakdown to PFOS . Production ended in 2002 “precursors” . Short-chain fluorotelomers . Inventory remains in many . PFOR – transformation to (6:2 and 4:2 FTS) locations sulfonates and carboxylates . May contain trace amts of . Contain or breakdown to . Long-chain fluorotelomers PFOA and PFOA precursors PFOS & PFHxS and possibly (8:2 FTS) can breakdown to . Considered lower in toxicity PFOA PFOA and reduced BAP 35 Fluorine-Free Foams
• Alternative to AFFF in some applications • Being used at some airports and industrial facilities in Europe, Australia, and other countries Fluorine Free Foam - MSDS • Do not contain PFAS or other persistent chemicals • Contain hydrocarbon surfactants, solvents, and stabilizers
Fluorine-Free Foams available since early 1900s TRCcompanies.com PFAS Toxicology & Risk Assessment
trcsolutions.com 37 Routes of Human Exposure to PFAS
Ingestion of: . contaminated drinking water . contaminated food (landfarming, homegrown produce) . fish/wildlife (biomagnification concerns)
Contact with other impacted media (air, soil, sediment)
Use of consumer products containing PFAS – generally low . ScotchguardTM treated fabrics/carpets . GoreTex® . Non-stick cookware . AFFF . Personal care products – shampoos, dental products trcsolutions.com 38 Toxicokinetics of PFAS
Easily absorbed, Stored in liver, Reabsorbed in Slowly excreted slowly metabolized, blood, kidney, and kidney / in urine and feces widely distributed muscle transported to bile
. Human half-life 2-10 years (up to 70 years for complete removal) . Have a low affinity for lipids and preferentially bind to proteins . Cross the placental barrier and are excreted into breast milk
TRCcompanies.com 39 Diverse Health Effects
. Developmental delays
. Liver toxicity
. Immune system changes
. Increased cholesterol
. Pregnancy-induced hypertension
. Kidney and testicular cancer
40 Uncertain Toxicity
Estimated safe level is low for PFOA/PFOS
. 20 ng/kg-day, based on 2016 EPA Office of Water evaluation ‒ 10 times more toxic than arsenic ‒ Target is the developing fetus and newborn ‒ Cancer endpoints occur at higher doses than non-cancer endpoints
Safe level is unknown for most PFAS
. Toxicity studies are continuing, but…. ‒ Difficult due to the number and variety of PFAS ‒ Responses differ between animals and humans ‒ No formal IRIS evaluation is scheduled
41 Ongoing National Initiatives
. July 2018 – ATSDR reviewed toxicity of 14 PFAS; published Draft Subchronic MRLs for 4 PFAS (PFOA, PFOS, PFHxS, PFNA) • Awaiting final report . Nov 2018 – EPA released draft toxicity assessments for Gen-X chemicals and PFBS • Comment period closed Jan 22, 2019 • Final values will replace PPRTVs for PFBS . Dec 2018 – EPA announced 5 additional PFAS (PFNA, PFBA, PFHxA, PFHxS, PFDA) will be reviewed for toxicity as part of IRIS Program • Public Comment Drafts anticipated 2020 trcsolutions.com MRL = Minimal Risk Level 42 Ongoing National Initiatives continued
. Feb 2019 – EPA published PFAS Action Plan outlining concrete steps to address PFAS and protect public health • Moving forward to develop MCLs for PFOA/PFOS
. April 2019 – CDC/ATSDR announced intent to conduct multi-site study on human health affects associate with PFAS exposure • Soliciting research applications from 6 communities • Pease Health Study 2018 protocols to be used and all results will be integrated
trcsolutions.com 43 Plug for ITRC PFAS Team
• Includes >350 members: industry, academia, DOD, regulatory, consulting, analytical labs and vendors
• Seven PFAS Fact Sheets: – AFFF Introduction – History and Use – Naming Conventions and Chemical Properties – Regulations and Guidance – Fate and Transport – Site Characterization, Sampling, Lab Methods – Remediation Technologies and Methods
• 2019 – Technical Guidance Document trcsolutions.com 44 Questions?
Elizabeth Denly, ASQ CMQ/OE P: (978) 656-3577 | E: [email protected] www.TRCcompanies.com