On October 7, 2024, the United States Environmental Protection Agency (“EPA”) issued recommended ambient surface water quality criteria and acute saltwater aquatic life benchmarks for PFOA and PFOS, as well as acute freshwater aquatic life benchmarks for eight PFAS. These are not regulatory standards, nor do they automatically become part of a State’s water quality standards. According to EPA they “provide information that States and Tribes may consider when adopting water quality standards.”
As explained by EPA:
States must adopt into their standards water quality criteria that protect the designated uses of their water bodies. States can establish water quality criteria based on the EPA’s recommended criteria, modify recommended criteria to reflect site-specific conditions, or develop proposed standards using on other scientifically defensible methods. A State’s or Tribe’s water quality criteria are not legally effective under the Clean Water Act until they have been adopted into a State’s or Tribe’s water quality standards and are approved by the EPA.
According to EPA, it develops recommended ambient water quality criteria for the protection of aquatic life based on the highest numeric concentrations of pollutants that are protective of aquatic ecosystems as a whole, and EPA includes specific recommendation on the duration (e.g., 1-hour average or 4-day average) and frequency (e.g., not to be exceeded more than once every 3 years) of the concentrations.
As to eight other PFAS, EPA issued aquatic life benchmarks, developed under section 304(a)(2) of the Clean Water Act . EPA explained that these benchmarks are informational values that the EPA generates when there are limited high quality toxicity data available and data gaps exist for several aquatic organism families. The EPA develops aquatic life benchmarks to provide information that States and Tribes may consider in their water quality protection programs.
Below are the two EPA tables regarding freshwater from the Federal Register announcement (2024-23024 (89 FR 81077)). Note that mg/L equate to parts per million.
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