U.S. EPA Proposes Regulating Some PFAS in Drinking Water

On 29 March 2023 the U.S. Environmental Protection Agency (EPA) issued a preliminary regulatory determination to regulate perfluorohexane sulfonic acid (PFHxS), hexafluoropropylene oxide dimer acid (HFPO-DA) and its ammonium salt (also known as a GenX chemicals), perfluorononanoic acid (PFNA), and perfluorobutane sulfonic acid (PFBS) and mixtures of these per- and polyfluoroalkyl substances (PFAS) as contaminants under the Safe Drinking Water Act (SDWA). The public comment period is open through 30 May 2023.

3E Review

This EPA action follows their 3 March 2021 final determination to regulate perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in drinking water. In addition to listing these substances as contaminants under the SDWA, the EPA also proposes a National Primary Drinking Water Regulation (NPDWR) and health-based Maximum Contaminant Level Goals (MCLG) for these four PFAS and their mixtures as well as for PFOA and PFOS.

The EPA proposes setting the health-based value, the MCLG, for PFOA and PFOS at zero. This enforceable limit is likely to reduce the likelihood of human health effects. Considering feasibility, including currently available analytical methods to measure and treat these chemicals in drinking water, the EPA proposes individual MCLs of 4.0 nanograms per liter (ng/L) or parts per trillion (ppt) for PFOA and PFOS. The agency also proposes using a Hazard Index (HI) approach to protecting public health from mixtures of PFHxS, HFPO-DA and its ammonium salt, PFNA, and PFBS because of their known and additive toxic effects and occurrence and likely co-occurrence in drinking water. The EPA proposes an HI of 1.0 as the MCLG for these four PFAS and any mixture containing one or more of them because it represents a level at which no known or anticipated adverse effects on the health of persons are expected to occur and which allows for an adequate margin of safety. The agency has determined it is also feasible to set the MCLs for these four PFAS and for a mixture containing one or more of PFHxS, HFPO-DA and its ammonium salt, PFNA, and PFBS as an HI of unitless 1.0. It is requesting comment on this action, including this proposed NPDWR and MCLGs, and has identified specific areas where public input will be helpful in developing the final rule. In addition to seeking written input, the EPA will hold a public hearing on 4 May 2023.

The complete docket of this proposed action can be found at EPA-HQ-OW-2022-0114; a link for comments can also be found at this docket.

3E Analysis

Interested parties should present comments on or before 30 May 2023. Comments on the information collection provisions submitted to the Office of Management and Budget (OMB) under the Paperwork Reduction Act are best assured of consideration by OMB if the bureau receives a copy of your comments on or before 28 April 2023.

The EPA will hold a virtual public hearing on the proposed PFAS NPDWR:

• Date: 4 May 2023
• Time: 11 A.M. to 7 P.M. EST

Go to the Proposed PFAS NPDWR Public Hearing page to register for the meeting by 2 May 2023.