This document summarizes the creation of an updated, comprehensive list of per- and polyfluoroalkyl substances (PFASs) that may have been on the global market. Over 4,700 CAS numbers were identified from various sources and categorized. There are limitations due to information gaps and challenges in categorization. Opportunities for developing this list further include creating an online database that can be regularly updated, addressing knowledge gaps, and expanding the PFAS terminology through cooperation.

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Zhanyun Wang and Martin Scheringer, ETH Zurich, Switzerland!
07/06/18! 1!
Toward a Comprehensive Global Database of PFASs:
Introducing the OECD 2018 List!

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Outline!
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§ Background, motivation and goals!
§ Methods!
§ Results!
§ Limitations, gaps and challenges!
§ Opportunities for way forward!
§ Acknowledgement !
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§ Per- and polyfluoroalkyl substances (PFASs), formerly referred to
as per- and polyfluorinated chemicals (PFCs), are a large class of
man-made chemicals since the 1940s.!
§ After numerous investigations since the late 1990s, a number of
so-called “long-chain” PFASs have now been recognized as
contaminants of high global concern.!
à High persistence, bioaccumulation potential, toxicity and
long-range transport potential!
à Ongoing regulatory and voluntary management actions!
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Background, motivation and goals!
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§ Meantime, many more structurally similar PFASs are on the
global market. !
à Overlooked legacy PFASs!
à Novel PFASs developed to replace long-chain PFASs!
§ A growing number of scientists, regulators and civil society
organizations are increasingly calling for effective and efficient
assessment and management of all PFASs.!
à E.g. Helsingør and Madrid Statements, UBA and KEMI
Workshops, ES&T Feature Article, etc. !
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Background, motivation and goals!
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§ Previous milestones on understanding the presence of PFASs on
the global market (and in the environment)!
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Background, motivation and goals!
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§ To synthesize existing information in the public domain,
and thus !
§ To establish an up-to-date, comprehensive list of PFASs that
may have been on the global market!
07/06/18!Zhanyun Wang! 6!
Background, motivation and goals!
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Methods!
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Step 3: harmonisation of substance information across
individual sources, subject to availability, to include
(1) CAS number.;
(2) chemical name registered at CAS;
(3) synonyms including trade names
(4) molecular formula;
(5) SMILES;
(6) previously used CAS number(s).
Step 4: compilation of PFASs from different sources
(1) use CAS numbers as the unique substance identifier;
(2) mark the presence of individual PFASs in each source
Step 5: categorisation of individual PFASs, including
(1) regulatory registration status
(2) structure category
(3) number of functional groups: mono- or multi-functional
(4) chain length of the "−CnF2n
−" or "−CnF2nOCmF2m
−" moiety
(5) linear or branched/cyclic isomer(s)
(6) (potential) degradability in the environment and biota
(7) non-polymer(s) vs. polymers
(8) single substance vs. a mixture of substances
(9) related substances (e.g., monomers, acid form of a salt)
(10) uncertainty of the categorisation
Step 1: checking if a substance has a CAS number
Step 2: Identification of PFASs
if a substance contains at least one of the following moieties
(1) −CnF2n
−, where n ≥ 3;
(2) −CnF2nOCmF2m
−, where n,m ≥ 1
Substances in individual sources
Substances with CAS numbers in individual sources
Identified PFASs in individual sources
the new list of identified PFASs
Sources considered in this study
1) Existing lists of PFASs
• OECD 2007 List
• KEMI 2015 List
2) National/Regional Chemical Inventories
• Australian Inventory of Chemical Substances (AICS)
• Canadian Domestic Substances List (DSL)
• Inventory of Existing Chemical Substances Produced or Imported in China
(IECSC)
• European Chemicals Agency Pre-registered Substances
• European Chemicals Agency Registered Substances
• Japanese List of Existing and New Chemical Substances (ENCS)
• Substances in Preparations in Nordic Countries (SPIN) Database
• US EPA TSCA Inventory
• US EPA Chemical Data Reporting (formerly Inventory Update Rule) Inventories
3) National/Regional Inventories of Chemicals in Specific Uses
• US FDA Inventory of Effective Food Contact Substance Notification (FCS)
• European Commission Database for Information on Cosmetic Substances and
Ingredients (CosIng)
4) National/Regional Inventories of Chemicals Subject to Specific Regulations
• Non-exhaustive list of chemical abstract service registry numbers for
substances subject to the Prohibition of Certain Toxic Substances Regulations,
2012, Canada
• Examples of PFOA and related substances based on the discussion of POPRC
12 under the Stockholm Convention, Japan
• Chemicals subject to TSCA Section 12(b) Export Notification Requirements
• Substances that have been assessed at Tier II under the Inventory Multi-tiered
Assessment and Prioritisation (IMAP) by the NICNAS, Australia
5) Scientific Databases
• SciFinder Database (those substances with reference(s) and commercial
sources that are included in the Database)

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Results!
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https://oecd.us18.list-manage.com/track/click?
u=df91cd39c652d7be5118c17f8&id=aeb27a5bc4&e=f4502cfec2!

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§ In total, 4730 CAS numbers were identified. !
§ 4730 CAS numbers ≠ 4730 PFASs, because!
(1) Some CAS numbers refer to (complex) mixtures of PFASs!
(2) Some CAS numbers may refer to the same PFAS(s)!
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§ The identified PFASs are diverse in terms of structure.!
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07/06/18!Zhanyun Wang! 9!
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Results!
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Results!
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PFASs
fluoropolymers (FPs)
polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluorinated ethylene propylene (FEP),
perfluoroalkoxyl polymer (PFA), polyvinyl fluoride (PVF), etc.
perfluoroalkyl /
per- and polyfluoroalkylether
acids (PFAAs)
perfluoroalkyl carboxylic acids (PFCAs), CnF2n+1-COOH
perfluoroalkane sulfonic acids (PFSAs), CnF2n+1-SO3H
perfluoroalkyl phosphonic acids (PFPAs), CnF2n+1-PO3H2
perfluoroalkyl phosphinic acids (PFPiAs), (CnF2n+1)(CmF2m+1)-PO2H
Fluorotelomer iodides (FTIs)
CnF2n+1CH2CH2I
perfluoroalkyl iodides (PFAIs)
CnF2n+1I
Fluorotelomer-based
substances
CnF2n+1CH2CH2-R
perfluoroalkane sulfonyl/carbonyl fluorides
(PASFs/PACFs) CnF2n+1SO2F / CnF2n+1CO2F
PASF/PACF-based substances
CnF2n+1SO2-R / CnF2n+1CO2-R
per- and polyfluoroether carboxylic acids (PFECAs), e.g. C2F5OC2F4OCF2COOH
perfluoropolyethers (PFPEs), e.g. HOCH2O-(CmF2mO)n-CH2OH
per- and polyfluoroether sulfonic acids (PFESAs), e.g. C6F13OCF2CF2SO3H
PFAA precursors
side-chain fluorinated polymers
e.g. (meth)acrylate, urethane or oxetane polymers
non-polymers
R = NH, NHCH2CH2OH, etc.
side-chain fluorinated polymers
e.g. (meth)acrylate, urethane or oxetane polymers
non-polymers
R = NH, NHCH2CH2OH, etc.
other PFASs
b) Other highly fluorinated substances that match the definition of PFASs, but have not yet been commonly regarded as PFASs
some hydrofluorocarbons (HFCs, e.g. CnF2n+1-CmH2m+1), hydrofluoroethers (HFEs, e.g. CnF2n+1OCmH2m+1) and hydrofluorooelfins (HFOs, e.g. CnF2n+1-CH=CH2)
that have a perfluoroalkyl chain of certain length
side-chain fluorinated aromatics, e.g. CnF2n+1-aromatic rings
perfluoroalkyl alcohols (CnF2n+1OH; e.g. (CF3)3C-OH, CAS number 2378-02-1), perfluoroalkyl ketones (e.g. CnF2n+1C(O)CmF2m+1) and semi-fluorinated ketones (e.g. CnF2n+1C(O)CmH2m+1)
Per- and polyfluoroether-based substances, e.g. C4F9OC2F4OC2F4OCF2-CH2OH (CAS number 317817-24-6)
a) Commonly recognised per- and polyfluoroalkyl substances (PFASs)
perfluorinated alkenes (CnF2n) and their derivatives (e.g. [(CF3)2CF]2C=C(CF3)(OC6H4SO3Na), CAS number 70829-87-7)
perfluorinated alkanes (CnF2n+2 )

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§ The list also contains additional information. !
§ Using US EPA Chemical Data Reporting as an Example!
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Results!
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§ Limitations associated with the format of the final list. !
à The list reflects only a snapshot of the state. !
§ Information gaps within the sources investigated.!
à Confidential business information.!
à Limited to no information on production and uses.!
à The current selection from SciFinder is limited.!
§ Information source gaps!
à E.g. company websites, peer-reviewed articles, other publicly
accessible inventories, lists and reports, etc. !
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Limitations, gaps and challenges!
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§ Challenges in categorizing PFASs!
à Associated with the vague descriptions of identified PFASs!
e.g. “poly(difluoromethylene)”, “1-propene, 1,1,2,3,3,3-
hexafluoro-, oxidized, polymd., reduced, hydrolyzed”, etc. !
à Associated with the current PFAS terminology!
e.g. no common terminology for newly identified groups !
such as side-chain fluorinated aromatics, etc. !
à Associated with knowledge gaps!
e.g. the degradability of many PFASs (such as
perfluoroalkenes and derivatives) remains unknown.!
07/06/18!Zhanyun Wang! 13!
Limitations, gaps and challenges!
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§ The OECD/UNEP Global PFC Group is hosting a new project to
expand the current PFAS terminology. !
§ Further cooperative actions are needed:!
à To develop an online database that may be regularly updated
and expanded!
à To ensure that basic information such as chemical identities
and uses is accessible to all stakeholders and in a clear and
consistent format!
à To address critical knowledge gaps including degradation!
07/06/18!Zhanyun Wang! 14!
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Opportunities for way forward!
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Acknowledgement!
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§ We gratefully acknowledge the OECD/UNEP Global PFC
Group for its general support and inputs. !
§ We gratefully acknowledge the Governments of Australia,
Canada and Sweden for providing data. !
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16. Thank you for your attention! !
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