A Duke University study has found microplastics in the fats and lungs of marine mammals.
The study that began in 2020 collected 32 tissue samples from whales, dolphins and seals. Two-thirds of those samples contained microscopic plastic particles, like polyester fibers from clothing.
Greg Merrill is the study's lead researcher and a fifth-year graduate student at Duke. His study suggests that “translocation” of microplastics occurs in marine mammals. That means once plastics are ingested, they can travel to various organs.
Since microplastics are what’s known as “lipophilic,” Merrill said they are attracted to the fatty parts of marine mammals, like blubber.
"I don't know if particles trapped in that layer of fat end up actually being metabolized out over time or not,” Merrill said. “But some very small proportion of the weight of an animal now contains plastic in it."
The samples were taken from North Carolina, California and Alaska. The majority were collected between 2019 and 2021, but some tissue samples were decades old. One tissue sample with plastic in it was from 2000.
"It's concerning because it just underscores the ubiquity of this problem and how long it's been happening,” Merrill said. “There's so much plastic in the ocean that it's ending up inside animals, and we don't quite understand all of the impacts that it might have."
Merrill's next phase of research will investigate those impacts. Prior studies show microplastics can damage internal tissues and may interfere with hormones. Merrill said there is a human risk to microplastics being present in marine mammals as well.
“The same type of harms that it might cause the animals, it could cause to the people that consume them,” Merrill said. “So, there is an exposure risk for native subsistence hunters or people globally that consume whale and seal meat.”
Merrill said the presence of such microplastics in marine mammals is also just one more indication of what humans might be consuming in fish as well.
