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 .