Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins

Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins Robert C. Buck James M. Franklin Urs Berger Jason Conder Ian T. Cousins Pim de Voogt Allan Astrup Jensen Kurunthachalam Kannan Scott A. Mabury S.P.J. van Leeuwen

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Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins 2011 Integrated Environmental Assessment and Management 10.1002/ieam.258 buck2011-perfluoroalkyl-and-polyfluoroalkyl buck2011-perfluoroalkyl-and-polyfluoroalkyl.txt, the project's staged copy 2ebbd3b045bea937763806ddd33d0a63fa00a016 cc-by-nc environmental-science

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them A NOMENCLATURE, WRITTEN DOWN BECAUSE THE FIELD'S NAMES HAD STOPPED REFERRING RELIABLY - 42 families and 268 compounds given recommended names, acronyms and structural formulas so that industry, science and regulators can mean the same substances by the same words Quotation withheld because this record is not cleared for redistribution. what to call these substances, when one compound has several names, one acronym has several referents, and one acronym is already taken by a treaty Quotation withheld because this record is not cleared for redistribution. the PFAS/PFC split, definitions of perfluoroalkyl and polyfluoroalkyl substances, a fluorinated-polymer/fluoropolymer distinction, an OECD-based numeric definition of 'long-chain', and a table of correct and incorrect usages Quotation withheld because this record is not cleared for redistribution. method Quotation withheld because this record is not cleared for redistribution. a vocabulary that grew faster than its referents could be pinned down - over 400 papers a year using names that had never been agreed Quotation withheld because this record is not cleared for redistribution. expert-consensus expert-consensus Quotation withheld because this record is not cleared for redistribution. THE PUBLISHED RULE FOR WHEN TWO FIELDS MAY SHARE AN ACRONYM: `many authors began using the acronym PFC and have defined it in many different ways. As a result, the meaning of the acronym PFC is unclear and not well defined ... the acronym PFC has been used in official KYOTO PROTOCOL documents since 1997 to specifically designate PERFLUOROCARBONS. Quotation withheld.` A criterion for tolerable homonymy - distance between the spheres, not the collision itself Quotation withheld because this record is not cleared for redistribution. AND BOTH DIRECTIONS OF THE MANY-TO-MANY FAILURE, IN ONE SENTENCE: `a given compound has often been denoted by a variety of different names and acronyms, or a given acronym has been used to represent different substances. In addition, names to describe broad groups of substances have proliferated that in some instances mistakenly portray substances that are very different from one another as being the same. As a result, the scientific literature for these substances has at times become confusing.` One name to many things, one thing to many names, and a third failure where the GROUP name asserts a false identity Quotation withheld because this record is not cleared for redistribution. AND THE NOMENCLATURE COMPROMISES CORRECTNESS AGAINST INSTALLED USAGE, ON PURPOSE: `We have nevertheless refrained from creating an all new nomenclature but have retained - as far as possible - the most popular terms and acronyms used by authors to date. In other words, our proposals result from A pragmatic compromise among textbook and/OR IUPAC CHEMICAL NOMENCLATURE, UNIVERSAL CONSISTENCY, AND FREQUENTLY ADOPTED `LEGACY` USAGE.` The same decision EWGSOP made keeping `sarcopenia`, stated here as a three-way trade-off with the axes named Quotation withheld because this record is not cleared for redistribution. AND TWO NOMENCLATURES COEXIST BY A DECLARED DIVISION OF LABOUR: `the substance terminology, names and acronyms proposed in this article are IN NO WAY INTENDED TO COMPETE WITH OR SUPPLANT IUPAC OR CAS NOMENCLATURE. The latter names are the designations of choice when A specific substance needs to be unequivocally identified, e.g., in official regulatory documents. Our intention is to provide terminology ... for pragmatic everyday use.` One vocabulary for identification, one for conversation, and the second says so - with the worked example running from a 58-character IUPAC name to the acronym EtFOSE Quotation withheld because this record is not cleared for redistribution. AND AN IDENTIFIER IS OFFERED AS THE REPAIR FOR A NAME: `Rigor can always be ensured by appending the appropriate CAS Registry Number when each compound is first mentioned in a publication. We encourage this practice and provide CAS numbers for many commonly discussed compounds.` The convenient name is allowed to be imprecise because a precise key travels beside it Quotation withheld because this record is not cleared for redistribution. AND A THRESHOLD IS ADOPTED SPECIFICALLY TO REMOVE SUBJECTIVITY: `PFASs ... are frequently referred to as `LONG-CHAIN` or `SHORT-CHAIN`. To avoid any subjectivity associated with these adjectives, we urge scientists to adopt the definition provided by the OECD` - eight carbons and greater for the carboxylic acids, SIX for the sulfonates. Two numbers for one adjective, in one paper Quotation withheld because this record is not cleared for redistribution. AND THE TWO NUMBERS DIFFER FOR AN EMPIRICAL REASON, NOT A CHEMICAL ONE: `The `LONG-CHAIN` DEFINITIONS FOR PFCAs AND PFSAs are different in number of C ATOMS BECAUSE a PFSA with a given number of carbons HAS A greater tendency to bioconcentrate and/OR BIOACCUMULATE than a PFCA with the same number of C atoms.` The class boundary tracks the behaviour the regulators care about, so one word carries two thresholds Quotation withheld because this record is not cleared for redistribution. AND LEGACY USAGE IS ENCODED DELIBERATELY IN A SUBSET RULE: `In compliance with time-honored usage within the industry, we recommend further that the term `FLUOROPOLYMERS` be applied only to a distinct subset of fluorinated polymers, namely, those made by (co)polymerization of olefinic monomers ... to form a carbon-only polymer backbone with F atoms directly attached to it.` The narrower term is kept narrow because the industry already uses it that way Quotation withheld because this record is not cleared for redistribution. AND FOUR WORDS ARE DECLARED INTERCHANGEABLE WITH A NAMED EXCEPTION: `the terms `SUBSTANCE,` `COMPOUND,` `CHEMICAL,` AND `SPECIES` ARE USED INTERCHANGEABLY for designating a given molecular structure, although it is recognized that in other contexts their meanings may not be identical. For example, in the European REACH legislation, a `SUBSTANCE` may include impurities and stabilizers in addition to the main constituent.` A local synonymy declared, scoped, and shown where it fails Quotation withheld because this record is not cleared for redistribution. A NEW AXIS FOR NAME-SPLITTING: LANGUAGE OF PUBLICATION. `Quotation withheld.` Every other split in this corpus runs across disciplines or across time. This one runs across a language boundary, and an English-language review has to name both to be searchable. Quotation withheld because this record is not cleared for redistribution. AND A SCIENTIFIC DEFINITION DEFERRING EXPLICITLY TO COMMERCIAL CUSTOM: `Quotation withheld.` The justification is neither composition nor function nor measurability - it is INCUMBENT USAGE IN A COMMERCIAL COMMUNITY, and the paper gives it as sufficient reason. Quotation withheld because this record is not cleared for redistribution. THE NOMENCLATURE HAS TO COVER MORE THAN IT LISTS: `Quotation withheld` `Selected` is the load-bearing word: the families are enumerable, the compounds are not Quotation withheld because this record is not cleared for redistribution. AND THE NAMES SIT ON TOP OF A COMBINATORIAL PROBLEM: `PFOS is routinely present in many environmental samples AS A mixture of the linear isomer and 10 BRANCHED ISOMERS, WHEREAS 89 congeners are theoretically possible.` One recommended name covers eleven observed substances out of eighty-nine possible ones Quotation withheld because this record is not cleared for redistribution. and the field it is trying to standardise was already producing over four hundred papers a year: `the scientific literature on the environmental and toxicological aspects of PFASs has burgeoned rapidly, and the rate of publication currently exceeds 400 articles per year` - a decade after the first reports. The nomenclature arrives after the usage it must harmonise Quotation withheld because this record is not cleared for redistribution. retaining the most popular existing terms and acronyms instead of minting a new system eliminates: a correct nomenclature nobody adopts - the failure mode of every naming reform · outcome: partial Quotation withheld because this record is not cleared for redistribution. appending the CAS Registry Number when a compound is first mentioned eliminates: ambiguity in the short convenient name, without making the short name longer · outcome: held Quotation withheld because this record is not cleared for redistribution. adopting the OECD's numeric definition of 'long-chain' rather than the adjective eliminates: 'any subjectivity associated with these adjectives' · outcome: held Quotation withheld because this record is not cleared for redistribution. PFAS PFAS Quotation withheld because this record is not cleared for redistribution. PFC PFC Quotation withheld because this record is not cleared for redistribution. fluoropolymers fluoropolymers Quotation withheld because this record is not cleared for redistribution. fluorinated polymers fluorinated polymers Quotation withheld because this record is not cleared for redistribution. PFCAs PFCAs Quotation withheld because this record is not cleared for redistribution. PFSAs PFSAs Quotation withheld because this record is not cleared for redistribution. tenside tenside Quotation withheld because this record is not cleared for redistribution. `PFAS` (this paper) - `perfluoroalkyl AND polyfluoroalkyl substances`: aliphatic substances containing the perfluoroalkyl moiety CnF2n+1-, covering BOTH the fully-substituted and the partly-substituted cases Quotation withheld because this record is not cleared for redistribution. `PFC` - reserved here EXCLUSIVELY for `perfluorocarbons`, because the Kyoto Protocol has used it that way since 1997; its use for `perfluorochemicals` is called `an unfortunate and inappropriate` choice Quotation withheld because this record is not cleared for redistribution. `fluoropolymers` vs `fluorinated polymers` - the broad term covers any polymer with F in a monomer unit; the narrow one is restricted to a `distinct subset` by `time-honored usage within the industry` Quotation withheld because this record is not cleared for redistribution. `long-chain` - defined numerically by the OECD to remove subjectivity, and with TWO different carbon counts: 8 or more for the carboxylic acids, 6 or more for the sulfonates Quotation withheld because this record is not cleared for redistribution. `tenside` / `surfactant` - TWO NAMES FOR ONE THING, SPLIT BY THE LANGUAGE OF THE PUBLISHING COMMUNITY, AND THE PAPER SAYS SO OUTRIGHT: `Quotation withheld.` Not two fields, not two decades - two languages. Quotation withheld because this record is not cleared for redistribution. extends → IUPAC and Chemical Abstracts Service nomenclature, which this paper explicitly does NOT seek to supplant - 'the designations of choice when a specific substance needs to be unequivocally identified' Quotation withheld because this record is not cleared for redistribution. extends → the OECD (2011) numeric definition of 'long-chain', adopted here to remove the subjectivity of the adjective Quotation withheld because this record is not cleared for redistribution. PFAS —distinct-from→ PFC PFAS PFC the relation itself is separately evidenced · strength of the relation: 0.95 · note: 'A GIVEN ACRONYM MAY…' This is the rule the corpus lacked for 'priming effect' meaning one thing in psychology and another in soil science: the homonymy is fine until the fields touch · the relation stated: two classes too closely related to share an acronym - the criterion is the DISTANCE BETWEEN THE SPHERES OF USE, not the collision itself Quotation withheld because this record is not cleared for redistribution. fluoropolymers —part-of→ fluorinated polymers fluoropolymers fluorinated polymers the relation itself is separately evidenced · strength of the relation: 0.95 · note: `In compliance with time-honored usage within the industry, we recommend further that the term `fluoropolymers` be applied only to a distinct subset of fluorinated polymers.` The containment is a naming decision, not a chemical fact - the narrower term could have been the broader one and the paper says why it is not · the relation stated: 'fluoropolymers' is restricted to a DISTINCT SUBSET of fluorinated polymers, in compliance with time-honoured industry usage Quotation withheld because this record is not cleared for redistribution. PFCAs —distinct-from→ PFSAs PFCAs PFSAs the relation itself is separately evidenced · strength of the relation: 0.95 · note: `The `LONG-CHAIN` DEFINITIONS FOR PFCAs AND PFSAs are different in number of C ATOMS because a PFSA with a given number of carbons HAS A greater tendency to bioconcentrate and/OR BIOACCUMULATE than a PFCA with the same number.` One word, two thresholds, and the gap between them is a measurement · the relation stated: 'long-chain' means eight carbons for one family and six for the other, because the sulfonates bioaccumulate more at the same chain length Quotation withheld because this record is not cleared for redistribution. A PUBLISHED RULE FOR WHEN TWO FIELDS MAY SHARE AN ACRONYM: `a given acronym may legitimately be used in different spheres of activity to denote different concepts, provided these activities are sufficiently disconnected from each other` A PUBLISHED RULE FOR WHEN TWO FIELDS MAY SHARE AN ACRONYM: `a given acronym may legitimately be used in different spheres of activity to denote different concepts, provided these activities are sufficiently disconnected from each other` Quotation withheld because this record is not cleared for redistribution. AND BOTH DIRECTIONS OF THE MANY-TO-MANY FAILURE, PLUS A THIRD: `a given compound has often been denoted by a variety of different names and acronyms, or a given acronym has been used to represent different substances ... names ... mistakenly portray substances that are very different from one another as being the same` AND BOTH DIRECTIONS OF THE MANY-TO-MANY FAILURE, PLUS A THIRD: `a given compound has often been denoted by a variety of different names and acronyms, or a given acronym has been used to represent different substances ... names ... mistakenly portray substances that are very different from one another as being the same` Quotation withheld because this record is not cleared for redistribution. AND A NOMENCLATURE THAT COMPROMISES WITH INSTALLED USAGE ON PURPOSE: `A pragmatic compromise among textbook and/OR IUPAC CHEMICAL NOMENCLATURE, UNIVERSAL CONSISTENCY, AND FREQUENTLY ADOPTED `LEGACY` USAGE` AND A NOMENCLATURE THAT COMPROMISES WITH INSTALLED USAGE ON PURPOSE: `A pragmatic compromise among textbook and/OR IUPAC CHEMICAL NOMENCLATURE, UNIVERSAL CONSISTENCY, AND FREQUENTLY ADOPTED `LEGACY` USAGE` Quotation withheld because this record is not cleared for redistribution. AND TWO NOMENCLATURES COEXISTING BY DECLARED DIVISION OF LABOUR: the recommended names are `IN NO WAY INTENDED TO COMPETE WITH OR SUPPLANT IUPAC OR CAS NOMENCLATURE`, which remain `the designations of choice when a specific substance needs to be unequivocally identified` AND TWO NOMENCLATURES COEXISTING BY DECLARED DIVISION OF LABOUR: the recommended names are `IN NO WAY INTENDED TO COMPETE WITH OR SUPPLANT IUPAC OR CAS NOMENCLATURE`, which remain `the designations of choice when a specific substance needs to be unequivocally identified` Quotation withheld because this record is not cleared for redistribution. AND ONE ADJECTIVE CARRYING TWO THRESHOLDS FOR A MEASURED REASON: `The `LONG-CHAIN` definitions for PFCAs and PFSAs are different in number of C atoms because a PFSA ... has a greater tendency to bioconcentrate and/or bioaccumulate` AND ONE ADJECTIVE CARRYING TWO THRESHOLDS FOR A MEASURED REASON: `The `LONG-CHAIN` definitions for PFCAs and PFSAs are different in number of C atoms because a PFSA ... has a greater tendency to bioconcentrate and/or bioaccumulate` Quotation withheld because this record is not cleared for redistribution. AND FOUR WORDS DECLARED INTERCHANGEABLE WITH THE EXCEPTION NAMED: `SUBSTANCE, COMPOUND, CHEMICAL, AND SPECIES ARE USED INTERCHANGEABLY ... For example, in the European REACH legislation, a SUBSTANCE MAY INCLUDE IMPURITIES AND STABILIZERS` AND FOUR WORDS DECLARED INTERCHANGEABLE WITH THE EXCEPTION NAMED: `SUBSTANCE, COMPOUND, CHEMICAL, AND SPECIES ARE USED INTERCHANGEABLY ... For example, in the European REACH legislation, a SUBSTANCE MAY INCLUDE IMPURITIES AND STABILIZERS` Quotation withheld because this record is not cleared for redistribution. `PERFLUOROALKYL SUBSTANCES ... for which ALL of the H atoms ... have been replaced by F atoms` PLUS `POLYFLUOROALKYL SUBSTANCES ... for which all H atoms attached to AT LEAST ONE (BUT NOT ALL) C atoms have been replaced`, provided they contain the perfluoroalkyl moiety CnF2n+1- PFAS Quotation withheld because this record is not cleared for redistribution. `perfluoroalkyl CARBOXYLIC acids with EIGHT carbons and greater` and `perfluoroalkane SULFONATES with SIX carbons and greater` - adopted `To avoid any subjectivity associated with these adjectives` long-chain Quotation withheld because this record is not cleared for redistribution. `a distinct subset of fluorinated polymers, namely, those made by (co)polymerization of olefinic monomers ... to form a carbon-only polymer backbone with F atoms directly attached to it` - restricted `In compliance with time-honored usage within the industry` fluoropolymers Quotation withheld because this record is not cleared for redistribution. with recommended names, acronyms, structural formulas and CAS registry numbers names the nomenclature had to supply Quotation withheld because this record is not cleared for redistribution. one adjective, two numbers, and the gap is a bioaccumulation measurement long-chain threshold Quotation withheld because this record is not cleared for redistribution. for PFOS alone - the recommended name covers eleven of eighty-nine isomers behind one name Quotation withheld because this record is not cleared for redistribution. a decade after the first reports of global occurrence publication rate the nomenclature must catch up with Quotation withheld because this record is not cleared for redistribution. the only arithmetic in the naming problem: 89 possible, 11 observed, 1 name - and the mixture `presents challenges in providing an accurate quantification` count of congeners Quotation withheld because this record is not cleared for redistribution. CnF2n+1- : the structural feature that decides membership of the PFAS family, and the reason `scattered` polyfluorinated compounds are excluded perfluoroalkyl moiety Quotation withheld because this record is not cleared for redistribution.

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