PFAS build up strongly in fish, and locally caught freshwater fish carry the highest levels by far, while most commercially sold marine fish test much lower. Fish is still a valuable source of protein and omega-3 fats. The practical answer is not to stop eating fish, but to know which fish concentrate PFAS, follow local advisories for waters you fish yourself, and lean toward the lower-risk options for regular meals.
Key takeaways
– Freshwater fish caught from lakes, rivers, and streams tend to have the highest PFAS levels; one U.S. study found median total PFAS of 9,500 ng/kg in fish fillets.
– Most commercially sold marine fish and shellfish test far lower, and U.S. regulators have not flagged them as a health concern apart from one imported product.
– You can keep eating fish by checking state and EPA advisories for locally caught fish and favoring lower-risk commercial options.
Why do PFAS build up in fish?
PFAS are a large family of synthetic chemicals used since the 1940s for their water, grease, and stain resistance. They are often called forever chemicals because their strong carbon-fluorine bonds resist breaking down in the environment and in living things. If you want the background on the chemistry and where these compounds come from, see our overview of what PFAS are.
One PFAS compound in particular, PFOS, binds to proteins in blood and the liver rather than to fat. That makes it accumulate in the tissues of fish over their lifetime, and it concentrates further as it moves up the food chain from small prey to larger predators. This process, called bioaccumulation, is why a fish that spends years in contaminated water can carry PFAS levels many times higher than the water it swims in.
How much PFAS is in freshwater fish?
The clearest data comes from a 2023 study published in the journal Environmental Research by researchers at the Environmental Working Group. Analyzing more than 500 fish fillet samples collected across the United States between 2013 and 2015 through EPA monitoring programs, they found a median total PFAS level of 9,500 nanograms per kilogram in fish from rivers and streams, and 11,800 nanograms per kilogram in fish from the Great Lakes. PFOS made up roughly 74 percent of the total.
To put that in everyday terms, the researchers calculated that eating a single serving of freshwater fish in a year was roughly equivalent, in terms of PFOS exposure, to drinking water contaminated at 48 parts per trillion for a full month. The study also reported that median PFAS levels in these freshwater fish were about 278 times higher than levels in commercially sold fish that the U.S. Food and Drug Administration had tested. That gap between locally caught freshwater fish and commercial fish is the single most important thing to understand about PFAS and seafood.
Which fish are higher versus lower risk?
Risk depends far more on where a fish comes from than on the species alone. Freshwater fish from contaminated waters, and predatory fish that eat other fish, sit at the higher end. Most open-ocean commercial fish and many farmed and shellfish options sit lower. The table below is a general guide, not a substitute for local testing data.
| Higher relative risk | Lower relative risk |
|---|---|
| Locally caught freshwater fish (bass, carp, catfish, perch, trout from lakes and rivers) | Most commercially sold ocean fish (cod, pollock, tuna, salmon) |
| Fish from waters near industrial sites, airfields, or known contamination | Smaller, shorter-lived species lower in the food chain |
| Large predatory freshwater fish that eat other fish | Many farmed fish raised in monitored, clean-water systems |
| Certain locally harvested shellfish from contaminated estuaries | Commercially tested shellfish shown as non-detect in surveys |
The pattern holds because commercial marine species are caught in large, well-mixed bodies of water where PFAS are far more diluted than in a small lake or a river downstream of a pollution source.
What do fish consumption advisories say?
Fish consumption advisories are official guidance from state agencies and the EPA telling people how often, if at all, it is safe to eat fish caught from specific waters. In July 2024, the EPA added PFAS to the list of contaminants it recommends states, tribes, and territories monitor in locally caught freshwater fish under the Clean Water Act, the first time PFAS appeared on that list.
Many states already issue PFAS-related fish advisories, including Michigan, Minnesota, Maine, New Jersey, Wisconsin, and others. These advisories are water-specific and species-specific, so a lake a few miles from another can carry very different guidance. If you or your family fish recreationally, checking your state environmental agency before you eat the catch is the most reliable step you can take. It is a bigger lever than any general rule of thumb, because it reflects actual measured levels in the water you are fishing.
What about commercially sold fish?
The picture for store-bought seafood is more reassuring. In the FDA’s 2022 targeted seafood survey, one or more PFAS was detected in 74 percent (60 of 81) of samples covering clams, cod, crab, pollock, salmon, shrimp, tilapia, and tuna. Detection, however, is not the same as a health concern: modern lab methods can find vanishingly small traces. The FDA concluded that, apart from one product, the PFAS levels measured in this seafood were not likely to be a human health concern at the amounts found.
The exception was canned clams imported from China, where the FDA detected elevated levels of PFOA and judged the estimated exposure to be a concern. That single finding aside, the agency’s testing supports the view that most commercially sold fish is a reasonable part of a normal diet. This is consistent with the freshwater study above, which found commercial fish carried a tiny fraction of the PFAS seen in locally caught freshwater fish.
How can I keep eating fish while limiting PFAS?
Fish delivers protein, omega-3 fatty acids, and micronutrients that are hard to replace, so the goal is smarter choices rather than avoidance. A few practical habits do most of the work. Favor commercially sold ocean fish for regular meals. Treat locally caught freshwater fish as an occasional food, and check your state advisory for the specific water first. If you catch your own fish often, vary your sources and species rather than eating repeatedly from one spot.
PFAS collect in the fillet tissue itself, so trimming skin and fat helps more with some other contaminants than with PFAS, which is worth knowing so you do not over-rely on preparation alone. Reducing exposure from other everyday routes matters too. Our guides on how to avoid PFAS in daily life and on PFAS in drinking water cover the sources that, for most people, add up alongside food. Because PFAS leave the body slowly, some readers also ask how to reduce PFAS already in the body, where the honest answer is that the strongest lever is limiting new exposure over time.
FAQ
Is it safe to eat fish with PFAS in it?
For most commercially sold fish, regulators have not identified a health concern at the levels typically found, and the nutritional benefits of fish are well established. The main caution is around locally caught freshwater fish, where levels can be much higher and where you should follow your state advisory.
Which fish have the most PFAS?
Locally caught freshwater fish from lakes, rivers, and streams tend to have the highest levels, especially larger predatory fish and fish from waters near known contamination. A 2023 study found a median total PFAS level of 9,500 ng/kg in U.S. freshwater fish fillets.
Does cooking remove PFAS from fish?
No. Unlike some contaminants, PFAS are not broken down by normal cooking temperatures and are bound within the muscle tissue of the fish, so frying, baking, or grilling does not meaningfully reduce them.
Is farmed or wild fish lower in PFAS?
It depends on the water source rather than the label. Farmed fish raised in monitored, clean-water systems and wild ocean fish from open water both tend to be lower risk than fish from contaminated freshwater. There is no blanket rule that one is always safer than the other.
How do I check if fish from my area is safe?
Check your state environmental or health agency’s fish consumption advisories, which are specific to individual waters and species. The EPA now recommends states monitor PFAS in locally caught freshwater fish, so more advisories are becoming available over time.
