The National Primary Drinking Water Regulations (NPDWR) for PFAS limits in drinking water have been announced. But that’s not the only action the U.S. EPA has taken in recent weeks. In this month’s PFAS News and Views, we focus on several recent developments as the agency works to finish the final mile in the PFAS Strategic Roadmap published in 2021.


First-Ever Enforceable Limits on PFAS in Drinking Water Announced

On April 10, at 5 AM ET, the EPA announced the much-anticipated limits on PFAS in drinking water set under the Safe Drinking Water Act. The announcement specified limits and other details that differ from those proposed just a little over a year ago. Here are some highlights:

  • The enforceable Maximum Contaminant Levels (MCLs) for PFOA and PFOS are 4 parts per trillion (ppt) individually. These limits are unchanged from the original proposal. In addition, the non-enforceable Maximum Contaminant Level Goals (MCLG) for these compounds remain at zero.

  • PFNA, PFHxS, and HFPO-DA (GenX ) have individual MCLs and MCLGs at 10 ppt. In the initial proposal, none of these compounds had individual MCLs. Instead, all three plus PFBS were included in the Hazard Index.

  • The Hazard Index will now apply for any mixture containing two or more of the following compounds: PFHxS, PFNA, HFPO-DA, and PFBS. The Health Based Water Concentration (HBWC) value for PFHxS is now 10 ppt instead of 9 ppt as originally proposed, and the Hazard Index is set at a unitless value of 1.

  • Systems must complete their initial monitoring within 3 years, but they now have 5 years to implement a solution.

  • Reduced monitoring trigger levels are 1/2 of the MCL for each compound rather than 1/3. The EPA Fact Sheet on Monitoring and Reporting goes into detail on how trigger levels are defined and how they are used to determine monitoring frequency.

The prepublication version of the rule can be found on the EPA’s website.


EPA Proposes Plan to Study PFAS Influent to POTWs

PFAS prepIn January of 2023, the EPA’s Effluent Guidelines Program Plan 15 called for a study on PFAS influent sent to Publicly Owned Treatment Works (POTWS), also known as municipal sewage treatment facilities. Late last month, the EPA published details of the planned study to its website. This study will look at PFAS in POTW influent, effluent, and sewage sludge through an OMB-approved Information Collection Request (ICR). Both a questionnaire and sampling will be required of a subset of large POTWs across the U.S. Public comments on the proposed study are due by May 28, 2024.


EPA Updates Interim Guidance on Disposal and Destruction on PFAS

On April 8, the EPA released version 2 of its Interim Guidance on the Destruction and Disposal of Perfluoroalkyl and Polyfluoroalkyl Substances and Materials Containing Perfluoroalkyl and Polyfluoroalkyl Substances. This 153-page document details the uncertainties surrounding currently available destruction technology (thermal) and disposal approaches (landfills and underground injection). Section 6 also provides more information on research around emerging approaches to PFAS disposal and destruction, including a framework for evaluating potential destruction technologies. Once published in the Federal Register, the guidance will remain open for public comment for six months.


EPA Makes Progress on PFAS Toxicity Assessments

The EPA’s Integrated Risk Information System (IRIS) contains toxicity and cancer risk assessments for hundreds of compounds. However, of the thousands of known PFAS, only a handful have completed the rigorous process required to be included in the IRIS database. In March, progress was made on assessing the toxicity of three PFAS.

EPA Issues Toxicity Testing Orders for NMeFOSE - Among other powers, the Toxic Substances Control Act (TSCA) grants the EPA the authority to require manufacturers of potentially toxic compounds to study the toxicity of these substances and turn over the data to the agency. On March 25, the EPA ordered 3M Company and Wacker Chemical Corporation to conduct and submit testing on the physical-chemical properties of 2-(N-Methylperfluoro-1-octanesulfonamido) ethanol, otherwise known as NMeFOSE.

Draft Toxicity Assessment Issued for PFNA - In early March, the EPA published a draft IRIS Toxicological Review of Perfluorononanoic Acid (PFNA) and Related Salts. The report concludes that there is inadequate evidence to show a link between PFNA and cancer effects. However, there is enough evidence to show a link between PFNA and developmental growth impairment in humans and to indicate or suggest a link to other adverse health effects. The report is now open for public comment until May 6. These comments will then be reviewed by the external peer review team before a final Toxicological Assessment is published in the IRIS (Integrated Risk Information System) database.

Another Milestone Met for PFHxS Toxicity Assessment – The toxicity assessment for PFHxS moved forward when three external peer review meetings were held, two in late February and one on March 1. Once the external peer review is complete, the PFHxS assessment is expected to go into final revisions.


What We’re Watching

The EPA has yet to finalize the designation of PFAS as hazardous substances under CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act) and hazardous constituents under RCRA (Resource Conservation and Recovery Act). Both of these actions stand to have a significant impact on our customers, so we will be watching them closely.

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