In an article published in the peer-reviewed journal Environmental Science and Technology, researchers from the University of Toronto discovered the potential toxicity of novel, non-fluorinated alkyl ether sulfate surfactants known to be used as alternatives to per- and polyfluoroalkyl substances (PFAS) in aqueous firefighting foams (AFFFs). The study did not confirm the exact identifies of these substances, and it is not clear whether or not similar alkyl ether sulfates are potentially also used in food packaging. The research had initially set out to investigate a high throughput in-silico method to screen and prioritize PFAS based on their affinity to bind to a key human protein.
Specifically, the study developed a method based on size-exclusion column co-elution (SECC) and non-target analysis to screen PFASs that bind to the human liver fatty acid binding protein (hL-FABP). The method is seen as an efficient way to prioritize compounds for more careful review. “Considering the fact that tens of thousands of compounds are detected in a single experiment, the method is very time effective to identify previously unknown toxic components in a high-throughput way,” corresponding author Hui Peng said.
In the study, the researchers assessed 74 PFAS and identified that 20 of them bind to the protein, 8 of which with a high affinity. Applying the same method to a new AFFF product, 31 new chemicals were found to bind to the protein, and they were revealed to be analogs of perfluorosulfonic acids as well as four homologues of non-fluorinated alkyl ether sulfates. Testing of contaminated lake water found that these alternative surfactants appear to be widely used even though there is limited data available on their potential toxicity. Hui Peng told Chemical Watch that they “speculate that non-fluorinated ionic surfactants may cause toxicities via similar pathways to fluorinated surfactants.”
Emma Davies (April 23, 2020). “PFAS study suggests non-fluorinated surfactants may be equally toxic.” Chemical Watch
Yang, D. et al. (April 6, 2020). “Nontarget Screening of Per- and Polyfluoroalkyl Substances Binding to Human Liver Fatty Acid Binding Protein.” Environmental Science and Technology