The EPA-finalized MCLs are 4.0 parts per trillion (ppt) for PFOA, 4.0 ppt for PFOS, 10 ppt for PFNA, 10 ppt for PFHxS, and 10 ppt for HFPO-DA (GenX) individually. Also, the NPDWR uses a Hazard Index (HI) MCL to limit any mixture containing two or more of PFNA, PFHxS, PFBS, and HFPO-DA. (see table)

This is the first time a Hazard Index approach has been used for a drinking water regulation but is a common tool used in other types of EPA regulation like the Superfund program, to understand health risk from chemical mixtures. The Hazard Index considers the different toxicities of PFNA, PFHxS, PFBS, and HFPO-DA. For these PFAS, water systems would use a hazard index calculation to determine if the combined levels of these PFAS in the drinking water at each system pose a potential risk and require action.

The most common water treatment technologies for removing PFAS from water include granular activated carbon (GAC), ion-exchange resin (IX), and high-pressure membranes (Nanofiltration/Reverse Osmosis). All these solutions capture and divert PFAS, creating a concentrated waste stream that will become increasingly challenging to dispose of, at greater costs. Ovivo’s integrated approach combines concentration, destruction, and polishing technologies to ensure a complete, and economically viable solution that destroys all types of PFAS to meet compliance. This integrated solution will reduce both operating costs and offsite liabilities around the disposal of adsorption media such as GAC and single-use IX resins.