Ultrashort Chain PFAS: The Next PFAS Concern?

When we discuss PFAS (Per- and Polyfluoroalkyl Substances), the focus is typically on the short-chain and long-chain varieties. These groups include many of the Perfluoroalkyl Carboxylic Acids (PFCA) and Perfluoroalkyl Sulfonic Acids (PFSA), which are routinely analyzed using published methods like EPA 1633A.

However, the scientific community is now raising concerns about ultrashort chain PFAS. These compounds have a shorter fluorinated tail, ranging from C1 to C3 chain lengths, compared to short-chain PFAS which start at C4. In addition to PFCA and PFSA groups, this category includes ultrashort versions of Per- and Polyfluoroether Carboxylic acids (PFECA) and Perfluorinated Sulfonylimides (PFSI). In fact, some of these "ultrashorts"-specifically bis(trifluoromethylsulfonyl)amine (TFSI) and Perfluoropropanoic acid (PFPrA)-have already been added to the EPA’s Regional Screening Limits (RSLs).

In some cases, the industry has shifted to using these smaller-chain PFAS as replacements for their longer-chain cousins. But why are these ultrashorts becoming a key area of concern?

The Challenges Posed by Ultrashorts

The unique chemistry of these compounds presents several significant challenges:

• Increased Mobility: With their shorter fluorinated tails, ultrashorts are more mobile in the environment. Unlike longer-chain PFAS, which tend to bind to soil, these more mobile compounds can travel faster and farther through groundwater. This means they can potentially reach drinking water systems more quickly.
• Data Gaps in Health Effects: We simply lack sufficient information on the potential health effects and bioavailability of ultrashort PFAS. More study is critical to determine the extent of any ecological and human health risks.
• Difficulty in Removal: Many existing water treatment systems were designed to capture longer-chain PFAS, making them less effective against these smaller molecules.
• Staggering Concentrations: The levels of some shorter-chain compounds being detected in aqueous samples are a major red flag. For instance, concentrations of trifluoroacetic acid (TFA) are sometimes detected at levels that dwarf their longer-chain counterparts at certain sites.

The high concentrations already seen in literature, coupled with data gaps in their potential risks, demonstrate a clear need for increased study into the occurrence, fate, and transport of ultrashort PFAS.

Next Steps:

Stay ahead of emerging contaminants like ultrashort PFAS. At Eurofins Environment Testing, we are continuously expanding our analytical capabilities to address the next generation of environmental concerns.

Contact us today to discuss how we can help you integrate ultrashort PFAS analysis into your environmental monitoring program.