What are Per and Polyfluoroalkyl Substances? - PFAS

Per- and polyfluoroalkyl substances (PFAS) are a large family of chemicals that contain carbon, fluorine and other elements. Historically, these may have been referred to under the term ‘PFC’ which stood for Per Fluorinated Chemicals. However, PFC is also used to mean ‘Per Fluorinated Carbons’ ie greenhouse gases and so this term is no longer used for PFAS compounds.

All PFAS contain a chain of carbon atoms bonded to fluorine atoms. The difference being that in perfluoroalkyl substances, all the carbons except the last one in the carbon chain, are attached to fluorine atoms whereas in polyfluoroalkyl substances, at least one, but not all, the carbons in the carbon chain are attached to fluorine atoms.

Per and Polyfluoroalkyl Substances (PFAS) are manmade fluorinated compounds which are not naturally found in the environment. Large amounts of PFAS have also been produced during historic manufacturing processes since the 1940’s. They are found in everyday items as well as being widely used in industrial applications coating additives as a surface-active agent and firefighting foams and so can enter the environment though releases into the air, soil, and water streams.

PFOS (Perfluoro octane sulfonate) and PFOA (Perfluoro octanoic acid) are the most commonly discussed PFAS, but PFAS is a class with many thousands of compounds.

PFAS are recognised as harmful as they are persistent and mobile in the atmosphere and aqueous environments, due to their chemical stability and low volatility They have therefore become known as “Forever Chemicals” because they don't break down in the natural environment or in our bodies.

How are PFAS being regulated?

Within the EU, PFOA and PFOS have been listed under the Stockholm Convention on Persistent Organic Pollutants (POPs) and as a consequence, are now restricted under the EU POPs Regulation. Another PFAS (PFHxS), less widely used than PFOA and PFOS but often found in the environment and in human biomonitoring, is currently being assessed for a restriction under REACH and is also considered for listing under the Stockholm Convention. 

Some longer chain PFAS (C9-C14 PFCAs Perfluorocarboxylic Acids) are not known to be intentionally used in the EU, but they can be present as impurities during the manufacture of other PFAS.

A restriction process under REACH is ongoing, following the proposed restriction by Denmark, Germany, the Netherlands, Norway, and Sweden and was submitted to ECHA on 13 January 2023.  Around 10,000 Per- and Polyfluoroalkyl substances (PFAS) are under review by ECHA.

Main PFAS Compounds found in water

There are hundreds of different PFAS compounds, but the following table details a list of the main PFAS that are considered for treatment – at least in drinking water applications.

 

No

Acronym(s)

Description

1

PFBA

Perfluorobutanoic Acid

2

PFPeA

Perfluoropentanoic acid

3

PFHxA

Perfluorohexanoic acid

4

PFHpA

Perfluoroheptanoic acid

5

PFOA

Perfluorooctanoic acid – linear and branched

6

PFNA

Perfluorononanoic acid

7

PFDA

Perfluorodecanoic acid

8

PFUnA; PFUdA; PFUnDA

Perfluoroundecanoic acid

9

PFDoA; PFDoDA

Perfluorododecanoic acid

10

PFTrDA;PFTriA

Perfluorotridecanoic acid

11

PFTeA; PFTeDA

Perfluorotetradecanoic acid

12

PFHxDA

Perfluorohexadecanoic acid

13

PFODA

Perfluorooctadecanoic acid

14

PFBS

Perfluorobutane sulfonic acid

15

PFPeS

Perfluoropentane sulfonic acid

16

PFHxS

Perfluorohexane sulphonic acid – linear and branched

17

PFHpS

Perfluoroheptane sulfonic acid

18

PFOS

Perfluorooctane sulfonic acid – linear and branched

19

PFNS

Perfluorononane sulfonic acid

20

PFDS

Perfluorodecane sulfonic acid

21

PFUnDS

Perfluoroundecane sulfonic acid

22

PFDoS; PFDoDS

Perfluorodecane sulfonic acid

23

HFPO-DA (Gen-X)

Hexafluoropropylene oxide-dimer acid or perfluoro-2-propoxypropanoic acid – (FRD 903)

24

HFPO-TA

Hexafluoropropylene oxide trimer acid

25

DONA:ADONA

4,8-dioxa-3H-Perfluorononanoic acid

26

PFMOPrA

Perfluoro-3-methoxypropanoic acid

27

NFDHA

Perfluoro-3,6-dioxaheptanoic acid

28

PFMOBA

Perfluoro-4-methoxybutanic acid

29

PFECHS

Perfluoroethylcyclohexane Sulphonate

30

3:3 FTCA

3-Perfluoropropyl Propanoic acid

31

5:3 FTCA

5:3 Fluorotelomer carboxylic acid

32

7:3 FTCA

2H,2H,3H,3H-Perfluorodecanoic acid

33

PFEESA

Perfluoro(2-ethoxyethane)sulphonic acid

34

6:2 Cl-PFESA;9Cl-PF3ONS

6:2 chlorinated polyfluoroalkyl ether sulfonate

35

8:2 Cl-PFESA;11Cl-PF3OUdS

11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid

36

4:2 FTSA; 4:2 FTS

4:2 Fluorotelomer sulfonic acid

37

6:2 FTSA; 6:2 FTS

6:2 Fluorotelomer sulfonic acid

 38

8:2 FTSA; 8:2 FTS

8:2 fluorotelomer sulfonic acid

39

FBSA; PFBSA

Perfluorobutane sulfonamide

40

FHxSA

Perfluorohexane sulfonamide

41

FOSA (PFOSA)

Perfluorooctane sulfonaminde – Linear and branched

42

MeFOSA; N-MeFOSA

N-methylperfluorooctane sulfonamide – Linear and branched

43

EtFOSA; N-EtFOSA

N-ethyl perfluorooctane sulfonamide – Linear and branched

44

MeFOSE

N-methylperfluorooctanesulfonamidoethanol

45

EtFOSE

N-ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide

46

NMeFOSAA; MeFOSAA; MePFOSAA

2-(N-Methylperfluorooctanesulfonamido) acetic acid

47

NEtFOSAA; EtFOSAA; EtPFOSAA

N-ethyl perfluorooctane sulfonamido acetic acid

 

 

 

 

MePFBSA

N-methylperfluor-n-butanesulfonamide

 

MePFBSAA

N-methylperfluor-n-butanesulfonylamide acetic acid

 

PFTrDS

perfluorotridecan sulfonic acid

 

10:2 FTS

10:2 fluorotelomer sulfonic acid

 

6:2 diPAP

6:2 fluorotelomer phosphate diester

 

6:2/8:2 diPAP

6:2/8:2 fluorotelomer phosphate diester

 

8:2 diPAP

8:2 fluorotelomer phosphate diester

 


https://echa.europa.eu/fr/-/echa-publishes-pfas-restriction-proposal

 

 

 

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