Aquatic Life Criteria - Perfluorooctane Sulfonate (PFOS)
- What is PFOS?
- How does PFOS affect Aquatic Life?
- 2024 Final Aquatic Life Criteria for Perfluorooctane Sulfonate (PFOS)
What is PFOS?
PFOS belongs to the per- and polyfluorinated substances (PFAS) group of chemicals. PFOS is an organic, human-made perfluorinated compound, consisting of an eight-carbon backbone and a sulfonate functional group. PFOS and its precursors were used in commercial products as surface treatments for soil and stain resistance of textiles, paper, and metals, and was used in applications such as in firefighting foams starting in the mid-1950s.
How does PFOS affect Aquatic Life?
PFOS is human-made molecule and has no biologically important functions or beneficial properties to aquatic life. The mechanisms underpinning the toxicity of PFOS to aquatic organisms, like other PFAS, is an active and ongoing area of research. Much work is still needed from a mechanistic perspective to better understand how the different modes of action elicit specific biological responses. The final aquatic life ambient water quality criteria are based on observed effects of PFOS to the survival, growth, and reproduction of aquatic organisms.
2024 Final Aquatic Life Criteria for Perfluorooctane Sulfonate (PFOS)
The U.S. Environmental Protection Agency has published final national recommended aquatic life criteria for PFOS in freshwater. These final criteria reflect the latest scientific knowledge regarding the effects of PFOS on freshwater organisms. The final PFOS criteria document contains acute and chronic criteria for freshwaters. The final criteria document also contains chronic criteria expressed as tissue-based concentrations to protect aquatic life from PFOS bioaccumulation. The chronic freshwater and chronic tissue criteria are intended to be independently applicable; no single criterion takes primacy. States and authorized Tribes can adopt these recommended criteria into water quality standards to protect against the harmful effects of PFOS on aquatic life.
Available PFOS toxicity data for estuarine/marine species allowed for the derivation acute estuarine/marine benchmarks through application of a New Approach Method (NAM). The acute estuarine/marine benchmark is also intended to be protective of aquatic life designated uses.
- Federal Register Notice: Final Recommended Aquatic Life Criteria and Benchmarks for Select PFAS
- Factsheet: Final Recommended Aquatic Life Criteria and Benchmarks for Select PFAS (pdf)
- Document: Final Aquatic Life Ambient Water Quality Criteria for Perfluorooctane Sulfonate (PFOS) (pdf)
- Response to Public Comments for PFOA and PFOS (pdf)