EPA Finalizes National Primary Drinking Water Standards for Select PFAS Compounds
The United States Environmental Protection Agency (EPA) announced a much-awaited National Primary Drinking Water Regulation (NPDWR) for six per- and polyfluoroalkyl substances (PFAS) on April 10, 2024. The final NPDWR comes a little over a year after EPA published a proposed NPDWR on March 14, 2023. The NPDWR establishes legally enforceable Maximum Contaminant Levels (MCLs) and non-enforceable Maximum Contaminant Level Goals (MCLGs) for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO, commonly known as GenX), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS). PFAS are a group of synthetic chemicals that are widely distributed and persistent in the environment.
Consistent with the proposed NPDW from March 2023, EPA established final concentration-based MCLs (4 parts per trillion, or PPT) for PFOA and PFOS. The final NPDWR establishes concentration-based MCLs of 10 ppt for PFHxS, PFNA, and HFPO-DA and retained a Hazard Index approach for a mixture of two or more of PFHxS, PFNA, HFPO-DA, and PFBS. The final MCLs are detailed in the table below.
The announcement of a final NPDWR for select PFAS is a significant milestone that Verdantas has been watching closely. Although number of individual states have established their own drinking water standards for PFAS, the final NPDWR will establish common standards for drinking water applicable across all 50 states and will likely lead to revisions of state drinking water and groundwater criteria over the coming months and years. At Verdantas, we anticipate the following near-term implications:
- For Superfund sites, the federal MCLs may now be considered in calculating and establishing cleanup criteria.
- States may move to either revise or establish their own MCLs and associated groundwater and cleanup standards for PFAS.
- The federal MCLs may also drive states to consider/reconsider leaching-based soil standards in light of the final MCLs.
Verdantas provides PFAS consulting services to our clients and has been tracking regulatory and technical developments related to PFAS for many years. If you are a public or private water system or have questions about state- or federally-regulated site assessment and remediation projects, please reach out to the Verdantas Area Manager in your region and we will connect you directly with one of our PFAS experts.
Contact:
Zack Smith, Environmental Assessment and Remediation Practice Leader
Email: ZSmith@verdantas.com
verdantas.com
