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The United States Environmental Protection Agency defines PFAS in the Drinking Water Contaminant Candidate List 5 as substances that contain "at least one of the following three structures: R−CF 2 −CF(R')R", where both the −CF 2 − and −CF− moieties are saturated carbons, and none of the R groups can be hydrogen; R−CF 2 −O−CF 2 ...
The timeline focuses on some perfluorinated compounds, particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) [1] and on the companies that manufactured and marketed them, mainly DuPont and 3M. [2] An example of PFAS is the fluorinated polymer polytetrafluoroethylene (PTFE), which has been produced and marketed by ...
A new EU drinking water directive issued in 2020 adopted PFAS limit values. The limit values are 0.1 μg/L for the sum of 20 PFASs including PFHxS, and 0.5 μg/L for the sum of all PFASs. This directive is binding for all EU member nations. It is a minimum directive, and member states can elect to adopt stricter regulations. [19]
Perfluorooctanesulfonic acid (PFOS) (conjugate base perfluorooctanesulfonate) is a chemical compound having an eight-carbon fluorocarbon chain and a sulfonic acid functional group, and thus it is a perfluorosulfonic acid and a perfluoroalkyl substance (PFAS).
For example, in a study sponsored by the Swedish EPA, Swedish ski wax technicians, who have high PFAS exposure, did not have significantly higher levels of PFHxA in their blood samples when compared to the general population median for their age groups, even while having concentrations of other PFAS, like PFOA, up to 44 times higher than the ...
Fluorosurfactants (PFAS) reduce surface tension by concentrating at the liquid-air interface due to the lipophobicity of polyfluorocarbons. Chlorofluorocarbons are also perfluorinated compounds, many of which were formerly used as refrigerants ( Freon ) until they were implicated in ozone degradation .
6:2-fluorotelomersulfonic acid (6:2-FTS) is a chemical compound that belongs to the group of fluorotelomersulfonic acids within the broader class of per- and polyfluorinated alkyl compounds (PFAS). Due to its structural similarity to perfluorooctanesulfonic acid (PFOS), it is also called H 4 PFOS.
Perfluorobutanesulfonic acid (PFBS) is a PFAS chemical compound having a four-carbon fluorocarbon chain and a sulfonic acid functional group. It is stable and unreactive because of the strength of carbon–fluorine bonds. It can occur in the form of a colorless liquid or a corrosive solid. [1]