Similar to the Montreal Protocol, increased regulatory pressure on PBT/vPvB substances in Europe and the USA was seen as a driver for the chemical industry to produce more hydrophilic, and hence mobile, substances . Individual fluoropolymer manufacturers have developed their own structurally similar per-and polyfluoroalkylether carboxylic acids (PFECAs) as replacements for PFOA, which was used as a processing aid in fluoropolymer production. However, as mentioned above, some of these replacements, including GenX, are similarly problematic despite being less bioaccumulative . To date, many monitoring programs have seen an increase in these replacements in water resources and fish due to increasing use and emissions . GenX and PFBS were identified as SVHCs under the EU REACH regulation in 2019 and were some of the first SVHCs that were considered an equivalent level of concern to PBT/vPvB substances . Thus, the phasing out of some PBT/vPvB substances such as the long-chain PFASs has led to burden shifting towards PMT/vPvM substances such as PFECAs .