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followed them. Soon afterward, many researchers defined it in various other ways
and started to use the acronym PFC. Consequently, the acronym PFC meaning is not
clear and well described. Furthermore, this choice has been considered inappropriate and unfortunate. In Kyoto Protocol documents acronym PFC has been used
officially since 1997 to specify the perfluorocarbons [7].
PFAS Nomenclature
One perfluoroalkyl moiety (C n F 2n + 1 -) is present in all PFASs at least [8], whereas
substances with incomplete hydrogen atom replacement by F atoms are known as
polyfluoroalkyl substances. Perfluoroalkyl acids (PFAAs) comprise perfluoroalkyl
sulfonic, carboxylic, phosphinic, and phosphonic acids and based on their functional group, they are differentiated. Perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) have been the main area of focus for the
research with 4–16 carbon atoms (C4–C16). We can define long-chain PFASs as
PFCAs with 7 or greater perfluorinated carbons and those PFSAs having six or
greater perfluorinated carbons. Presence of fluorinated carbon chain enables these
chemicals to have both oleophobic and hydrophobic properties but deprotonation of
head group of many PFASs makes them highly stable in solution. High solubility of
PFASs in water results into their accumulation in rivers, groundwater and ocean,
and pollution of resources of drinking water marine mammals and fishes. Precursors
of PFAA, which are referred to as “precursors,” are chemical compounds that can be
broken down to PFAAs biotically or abiotically [9, 10]. Before disposition in the
areas that are far away from the sources of pollution volatile precursors may be
conveyed to long distances in the atmosphere [11, 12]. During the analysis of standard PFAA mostly precursors are not measured, which may result in under estimation of exposure to humans as they are degraded to short-chain PFAAs in the human
body [13, 14].
Chemistry and Chemical Properties
Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and their
derivatives are the most known chemicals among PFASs.
Chemical Properties
• PFOS, PFOA and their salts are soluble in water and may globally spread through
seawater currents [15].
• The most commonly used structures are more complex derivatives of these
chemical substances, for example, fluorotelomers and sulfonamides.
18 Role of Perfluoroalkyl Substances as EDCs in Metabolic Disorders
followed them. Soon afterward, many researchers defined it in various other ways
and started to use the acronym PFC. Consequently, the acronym PFC meaning is not
clear and well described. Furthermore, this choice has been considered inappropriate and unfortunate. In Kyoto Protocol documents acronym PFC has been used
officially since 1997 to specify the perfluorocarbons [7].
PFAS Nomenclature
One perfluoroalkyl moiety (C n F 2n + 1 -) is present in all PFASs at least [8], whereas
substances with incomplete hydrogen atom replacement by F atoms are known as
polyfluoroalkyl substances. Perfluoroalkyl acids (PFAAs) comprise perfluoroalkyl
sulfonic, carboxylic, phosphinic, and phosphonic acids and based on their functional group, they are differentiated. Perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) have been the main area of focus for the
research with 4–16 carbon atoms (C4–C16). We can define long-chain PFASs as
PFCAs with 7 or greater perfluorinated carbons and those PFSAs having six or
greater perfluorinated carbons. Presence of fluorinated carbon chain enables these
chemicals to have both oleophobic and hydrophobic properties but deprotonation of
head group of many PFASs makes them highly stable in solution. High solubility of
PFASs in water results into their accumulation in rivers, groundwater and ocean,
and pollution of resources of drinking water marine mammals and fishes. Precursors
of PFAA, which are referred to as “precursors,” are chemical compounds that can be
broken down to PFAAs biotically or abiotically [9, 10]. Before disposition in the
areas that are far away from the sources of pollution volatile precursors may be
conveyed to long distances in the atmosphere [11, 12]. During the analysis of standard PFAA mostly precursors are not measured, which may result in under estimation of exposure to humans as they are degraded to short-chain PFAAs in the human
body [13, 14].
Chemistry and Chemical Properties
Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and their
derivatives are the most known chemicals among PFASs.
Chemical Properties
• PFOS, PFOA and their salts are soluble in water and may globally spread through
seawater currents [15].
• The most commonly used structures are more complex derivatives of these
chemical substances, for example, fluorotelomers and sulfonamides.
18 Role of Perfluoroalkyl Substances as EDCs in Metabolic Disorders