The Substitute May Be Worse Than the Problematic Product. Change Doesn't Always Prove Positive.

[NNadir]

Most scientifically educated people understand that environmentally persistent perfluorinated chemicals, the general class of "PFAS" are rising as a severe environmental and health threat.

I'm not going to throw a lot of time into discussing this paper, since it's open sourced and free to read, but it evaluates the possible issues with the replacements of some of the worse PFAS compounds now recognized as extremely problematic.

The paper in question is this one: Perfluoroalkane Sulfonamides and Derivatives, a Different Class of PFAS: Sorption and Microbial Biotransformation Insights Donghui Ma and Christopher I. Olivares Environmental Science & Technology 2025 59 (22), 10734-10749.

There's lots of pictures of the structures of the replacement molecules in the text if one is interested.

Some excerpts from the text:

Perfluoroalkane sulfonamides and their derivatives (FASAs) are an emerging class of perfluoroalkyl and polyfluoroalkyl substances (PFAS). FASAs have a perfluoroalkyl chain attached to a sulfonamide group, with possible additional N-substitutions (Table 1). A detailed list of FASAs, including their acronyms, CAS numbers, and chemical structures, is provided in Table S1 of the Supporting Information. FASAs have been used alongside other PFAS in various industrial and consumer products, such as aqueous film-forming foams (AFFF), (1,2) fabric protectors, (3) and firefighter turnout gear textiles. (4) Notably, FASAs continue to be used today, with some serving as replacements for legacy PFAS. Some short-chain FASAs, including perfluorobutane sulfonamide (FBSA; subclass 1 in Table 1) and perfluorobutane sulfonamide ethanol (FBSE; subclass 2), have recently substituted perfluoroalkyl acids (PFAAs) in semiconductor manufacture. (5,6) N-Ethyl perfluorooctane sulfonamide (EtFOSA, subclass 1) has been extensively used as an active ingredient in the pesticide sulfluramid. (7) Glüge et al. (8) noted that three FASAs (potassium N-ethyl perfluorooctane sulfonamidoacetate (subclass 5), perfluorooctane sulfonamidoalkyl ammonium iodide (subclass 7), and perfluorooctane sulfonamidoalkyl ammonium chloride (subclass 7)) are among the PFAS with high usage frequency, because they have more than ten assigned applications in commerce. With the recent availability of standards and advancements in suspect screening techniques, the detection frequency of FASAs in environmental and biological samples has increased. (2,9−14) Concerningly, FASAs exhibit a potential biological toxicity. FASAs were the only type of PFAS that influenced developmental, morphological, and behavioral outcomes in zebrafish embryos. (15,16) FOSA, MeFOSA, and FHxSA even showed higher toxicity than perfluorooctanesulfonate (PFOS). (16) The sulfonamide group is associated with antimicrobial properties, a characteristic that has been exploited in the development of many nonfluorinated antibacterial agents. (17) Unlike PFAAs, which are anionic, FASAs can exist in protonated forms at environmentally relevant pH levels. (18) This unique property and varying nonfluorinated moieties affect their environmental transport and fate, making them distinct from the majority of PFAS

Sorption and microbial transformation affect the transport and fate of FASAs in the environment. Previous studies demonstrated that PFAA sorption to soil is controlled by hydrophobic and electrostatic interactions. PFAA adsorption increases with sediment organic matter content, solution ionic strength, and perfluoroalkyl chain length. (20) Perfluoroalkanesulfonates (PFSAs) show higher adsorption than perfluoroalkyl carboxylic acids (PFCAs) with comparable chain lengths. (21,22) Due to the different electrostatic charge (zwitterionic and neutral) compared to PFAAs (anionic) and diverse terminal functional groups of FASAs, their sorption mechanisms are expected to be more complex. To date, the sorption of FASAs in environmental media has been intermittently reported along with PFAAs data, and few dedicated studies on FASAs sorption exist. Beyond soils and aquifer solids, the sorption onto microbial biomass and biofilm can also influence the retention and transport of FASAs in environmental matrices. (23) PFAS sorption onto biomass has just started to be evaluated. (24−26)

PFAS are often considered biologically recalcitrant, although this primarily applies to PFAAs. (27) While some studies have reported PFAAs loss in various microbial cultures, the mechanisms continue to be debated and PFAAs remain biologically recalcitrant in most environmental settings. (28−32) In contrast, FASAs have been shown to undergo microbial transformation in natural environments, leading to the formation of terminal products─PFAAs, primarily PFSAs....

From the conclusion:

...FASAs differ from fluorotelomers in their diverse charged properties and antibacterial characteristics. This review examined the sorption and microbial transformation of FASAs to clarify their complex environmental fate. Compared with fluorotelomers, FASAs exhibit stronger sorption onto soil and greater resistance to microbial transformation. Despite the slow transformation, the terminal end products, PFSAs, become more mobile...

It behooves me to note that fuel cells, which the fossil fuel industry and its supporters trying to rebrand as "hydrogen" are perfluorinated polymers. Happily the affectation about a "hydrogen economy" is bullshit, but efforts to sell it will be involved in this particular set of environmental problems. Hydrogen is worse than the product it purports to replace, just as apparently the PFAS substitutes are apparently, in some cases, worse than the PFAS themselves.

[WhiteTara]

1. We seem determined to

Kill ourselves and the entire planet.

Thanks for the enlightening article

[littlemissmartypants]

2. Interesting. TY.