A new study has revealed that sea otters living along Canada’s Pacific coast have surprisingly high levels of toxic “forever chemicals” in their bodies—especially those living near large cities and busy shipping routes.
The research, published in Environmental Toxicology and Chemistry, examined a group of chemicals known as per- and polyfluoroalkyl substances, or PFAS.
These man-made chemicals are used to make products that resist heat, grease, and water—such as food packaging, nonstick cookware, waterproof clothing, cosmetics, firefighting foam, and electronics.
PFAS are often called “forever chemicals” because they do not break down easily in the environment. Instead, they spread through air, soil, and water, eventually ending up in living organisms.
PFAS can harm both animals and humans. They can disrupt hormones, weaken the immune system, damage organs, and affect reproduction.
Although some PFAS have been banned or phased out, they remain widespread and continue to accumulate in ecosystems.
Scientists are increasingly concerned about how these chemicals affect marine life, especially top predators like sea otters and killer whales.
Sea otters are particularly vulnerable because of their diet and habitat. They live in coastal areas close to human activity and eat large amounts of seafood—about a quarter of their body weight every day.
This makes them excellent indicators of local pollution levels. Sea otters also do not migrate, so their contamination levels reflect the chemical pollution of nearby waters where people also harvest seafood.
Researchers from Canada collected liver and muscle samples from 11 sea otters found dead along the British Columbia coast. They tested 40 different PFAS compounds and found eight of them in every single animal.
Concentrations varied between individuals, but levels were consistently higher in the liver than in the muscles. Only one chemical—perfluorooctanesulfonamide, once used in 3M’s Scotchgard—was found in both tissues.
On average, sea otters living closer to cities and shipping lanes had more than three times the amount of PFAS compared to those from remote areas. This pattern suggests that urban runoff and industrial pollution are major sources of contamination.
The study also builds on earlier research showing that California sea otters with higher PFAS exposure are more likely to die from diseases. Together, these findings highlight a growing threat to marine wildlife and ecosystems.
As sea otters are important indicators of coastal health, their contamination serves as a warning that “forever chemicals” are not only harming wildlife—but could also be affecting the safety of the seafood we eat.
