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Regulatory Updates

EPA Proposes Aquatic Life Criteria for PFOA and PFOS

Emily Larson & Catriona V. Smith (Cat), R.E.M | May 23, 2022

On May 3, 2022, under the Clean Water Act (CWA), the United States Environmental Protection Agency (EPA) proposed the first aquatic life criteria for both short-term and long-term toxic effects from Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS) (87 FR 26199). As part of the EPA’s PFAS Strategic Road Map, the draft criteria represent the latest state-of-the-science regarding the toxic effects of PFOA and PFOS on freshwater organisms.

Aquatic life criteria are established for ambient water to protect fish, invertebrates, and other aquatic life from adverse effects associated with the exposure to pollutants. While the draft criteria have undergone external peer review, public comments can still be received on or before July 2, 2022,  before the recommended values are published as final.

The recommended criteria are based on:

  • Survival, growth, and reproduction endpoints
  • Invertebrate (whole body) and fish (whole body and muscle) criteria
  • Acute (criterion maximum concentration [CMC]) water criteria
  • Chronic (criterion continuous concentration [CCC]) water criteria

The aquatic life criteria are the highest concentrations of PFOA and PFOS that can exist in ambient waters that are not expected to pose a significant risk to the majority of species in a given environment or water body. The recommended values below are intended to protect designated uses (aquatic life) and provide a basis for controlling the discharge of pollutants.

In addition to these criteria, state and authorized tribes may adopt other scientifically defensible water quality criteria, but due to high cost and complexity, states typically adopt EPA’s guidance for setting toxic criteria. Of note, the proposed chronic aquatic water quality levels (PFOS – 8,400 ng/L; PFOA – 94,000 ng/L) are two to three orders of magnitude higher than the human health EPA Health Advisory Levels for PFAS in drinking water (70 ng/L).

Who does this affect?

While these aquatic life criteria are not legally enforceable, the publishing of these values gives us an idea of which clients may be impacted and other potential activity.

  • Sites or facilities near or containing environmentally sensitive habitats (e.g., rivers and streams, wetlands, vernal pools, threatened and endangered [T&E] species areas, etc.) potentially impacted by PFAS may become subjected to PFAS investigations and monitoring
  • Criteria may be adopted to existing state water quality standards or incorporated into discharge permits
  • There may be an increase in screening level aquatic assessments at PFAS-impacted sites with ecological habitats

Actions you can take:

  • Develop a plan to respond to state agency comments should the aquatic life criteria be incorporated into discharge permits
  • Assess and identify your potential vulnerability if you discharge directly to surface waters
  • Develop a risk mitigation plan to help understand your risk level
  • Implement a sampling and analysis program under attorney/client privilege if needed

Finally, these criteria form the foundation for the CWA regulatory programs and enforcement actions concerning PFAS and aquatic life. The publishing of these values is the initial step to creating federal enforceable regulations.


Emily Larson

Emily Larson has more than 10 years of experience modeling the bioaccumulation of semivolatile compounds and metals in ecological systems, modeling exposure to human and ecological receptors, and preparing human health and ecological risk assessments. She has experience conducting risk assessments with emerging contaminants, specifically per-and polyfluoroalkyl substances (PFAS). In addition, she serves as a technical expert on PFAS within the intermountain region for TRC. She has experience with Superfund (CERCLA) as well as several state-led programs specifically in the Inter Mountain West and Pacific Northwest regions. Emily has worked with several clients in both the private and the public (state and federal) sector. She can be reached at

Catriona Smith

Catriona (Cat) Smith has over 30 years of professional experience in the interpretation and application of regulations for industrial facilities relating to compliance, remediation and negotiations with regulatory agencies. Her clients include upstream and downstream oil and gas, chem-pharma, petrochem, manufacturing and federal, state, and local governments. Ms. Smith is a Vice President and Environmental Sector Market Director for TRC, with nationwide responsibilities to manage our clients’ PFAS challenges, support and grow our Oil and Gas clients and bring multi-disciplinary solutions to their complex projects. Contact Cat at

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