If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Persistent Pollutants

Toxic PFAS found in freshwater fish

Environmental advocacy group pushes for uniform fish consumption advisory across US

by Britt E. Erickson
January 18, 2023 | A version of this story appeared in Volume 101, Issue 3


a person's hand holding a fishing rod overlooking a river
Credit: Shutterstock
An environmental group has sounded the alarm over high levels of perfluorooctanesulfonic acid in freshwater fish.

Fish caught in rivers, streams, and lakes across the US contain high levels of toxic per- and polyfluoroalkyl substances (PFAS), according to a new study (DOI: 10.1016/j.envres.2022.115165) by scientists at the Environmental Working Group (EWG). The advocacy group says the findings are particularly concerning for people whose survival depends on catching and eating freshwater fish.

The researchers analyzed PFAS data collected from 2013–2015 by the US Environmental Protection Agency on more than 500 freshwater fish. They found an average of 9.5 ppb PFAS in fish from US rivers and streams and 11.8 ppb in fish from the Great Lakes. Perfluorooctanesulfonic acid (PFOS) was the most commonly found PFAS, averaging 74% of the total PFAS.

For comparison, the scientists looked at data from the US Food and Drug Administration on PFAS in commercially relevant fish in 2019–2022. They report that the average amount of PFAS in freshwater fish was 280 times more than that found in commercially available fish sold in the US.

The FDA has not established a safe level for PFAS in fish. Several states have issued fish consumption advisories based primarily on PFOS levels in freshwater fish, but those levels vary widely by state.

“There should be a single health protective fish consumption advisory for freshwater fish across the country,” Nadia Barbo, a graduate student at Duke University and lead researcher on the study, says in a statement.

In June, the EPA tightened health advisory limits for two of the most toxic PFAS—perfluorooctanoic acid (PFOA) and PFOS—in drinking water. The limits recommended by the EPA—0.004 parts per trillion (ppt) for PFOA and 0.02 ppt for PFOS—are several orders of magnitude lower than the levels found in freshwater fish.

PFOA and PFOS are associated with reproductive, developmental, immunological, and liver effects, as well as certain cancers. Although they are no longer intentionally made in the US, the two chemicals contaminate drinking water nationwide.

The EWG is urging the EPA to stop industrial discharges of PFAS, which end up in rivers and streams and contaminate fish. PFAS are a class of synthetic chemicals known for repelling water and grease. Often called forever chemicals, they are slow to break down in the environment and in people.



This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.