US finally gets nationwide regulation of PFAS in drinking water

The US’s first national and enforceable drinking water standards for six per- and polyfluoroalkyl substances (PFAS) were announced by the US Environmental Protection Agency (EPA) yesterday. The long-awaited final rule sets legally imposed limits for these chemicals. Although environmental and health organisations celebrated the new regulations, the chemical industry and water utilities have serious concerns.

In the new regulations, the EPA has set limits on five individual PFAS, and a ‘hazard index’ for mixtures of various PFAS. For the two most well-known and best studied of these substances – perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) – the limit is 4 parts per trillion (ppt) and 10ppt for perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and hexafluoropropylene oxide-dimer acid (HFPO-DA) – also known as GenX. Combinations of two or more of PFNA, PFHxS, GenX and perfluorobutane sulfonate (PFBS) also face limits.