Just announced, the U.S. Environmental Protection Agency (EPA) is proposing a National Primary Drinking Water Regulation (NPDWR) to establish Maximum Contaminant Levels (MCLs) for six PFAS in drinking water. These include PFOA and PFOS as individual contaminants, and PFHxS, PFNA, PFBS, and HFPO-DA (or GenX Chemicals) as a PFAS mixture. Additionally, EPA is proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS.
The proposed MCL levels for PFOA and PFOS are four parts per trillion (4.0 ppt). The other four PFAS proposed MCLs will be calculated using a hazard index, a tool to evaluate potential health risks from exposure to chemical mixtures. The proposed rule would require public water systems to monitor for these PFAS, notify the public of these levels of PFAS, and reduce the levels of these PFAS in drinking water if they exceed the proposed standards.