Key Takeaways

• What Happened? The U.S. Environmental Protection Agency (EPA) published its final recommended aquatic life water quality criteria and benchmarks for two per- and polyfluoroalkyl substances (PFAS)—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)—under the Clean Water Act. EPA also published freshwater aquatic life benchmarks for eight additional PFAS. While non-binding, these recommendations serve as guidance for States and Tribes to set their own water quality standards to regulate their water bodies. Such actions could, in turn, result in new effluent and/or benchmark limitations for discharge permits.
• Who Is Affected? States, Tribes, industries, municipalities, and trade organizations throughout the country.
• Next Steps? Affected entities should consider monitoring their States’ next steps in adopting new water quality criteria in anticipation of any further changes. For more information, please contact the authors.

The U.S. Environmental Protection Agency (EPA) recently published its final recommended water quality criteria and benchmarks for certain PFAS under Section 304 of the Clean Water Act (CWA), 33 U.S.C. § 1314. These national water quality criteria and benchmarks establish maximum concentrations of certain PFAS that States and Tribes may consider as the basis for setting water quality criteria (which may be incorporated into water quality standards) for waters designated for use as aquatic ecosystems. This action represents the first time EPA has issued such water quality recommendations for PFAS.

EPA generally issues water quality criteria when the agency possesses a minimum level of toxicity data for aquatic animals and issues benchmark values when the agency has more limited data. While these recommendations are non-binding, States and Tribes can use them as guidance when adopting their own CWA water quality standards to protect the designated uses of their water bodies. EPA must then approve those standards before they become legally effective, at which point they become the basis for effluent limitations in National Pollutant Discharge Elimination System (NPDES) permits. EPA’s recommendations, therefore, represent the first step toward potential new effluent limitations for PFAS in discharge permits.

EPA published three sets of recommendations. First, it set freshwater aquatic life ambient water quality criteria for (PFOS) and (PFOA). Several of these criteria are drastically lower than the values EPA proposed in 2022. EPA claims the freshwater aquatic life water quality criteria for PFOS and PFOA establish maximum concentrations averaged over a given period that, if not exceeded, should protect aquatic ecosystems. EPA set forth acute and chronic water column criteria (describing short-term and long-term exposures to pollutant concentrations in the water), as well as chronic animal tissue concentrations criteria (describing pollutant concentrations accumulated in fish and invertebrate tissues). The specific criteria are as follows:

Freshwater Aquatic Life Recommended Criteria:

Second, EPA issued acute saltwater benchmarks that EPA believes represent the maximum concentrations of PFOS and PFOA expected to protect aquatic life from short-term effects in saltwater. EPA specifies that these benchmark concentrations should not exceed a one-hour average more than once in three years and are set forth in the following table:

Acute Saltwater Recommended Benchmarks for PFOS and PFOA:

Third,EPA established acute freshwater benchmarks for each of eight other PFAS, as follows:

Acute Saltwater Recommended Benchmarks:

EPA’s issuance of these recommended criteria and benchmarks is just the latest of several actions the agency has taken regarding PFAS under various environmental laws. In April 2024, EPA finalized the first federal water drinking standards for PFAS, and listed PFOA and PFOS as hazardous substances under CERCLA. EPA has also proposed adding 9 PFAS to the list of hazardous constituents under RCRA regulations, and 16 PFAS and 15 categories of PFAS to chemicals subject to reporting in the Toxic Release Inventory under EPCRA and PPA. EPA’s proposed rule related to effluent limitation guidelines applicable to the Organic Chemicals, Plastics, and Synthetic Fibers point source category to address PFAS discharges from manufacturers is pending at OMB.