Whales and Dolphins Are Now Partly Made of Plastic: Study

Whales and dolphins are now partly made of plastic due to pollution in the ocean, a study has found.

The study published by a graduate student at Duke University in Environmental Pollution found that of those studied, two-thirds of marine mammals had microscopic plastic particles embedded into their fats and lungs.

Samples from 32 stranded mammals in Alaska, California and North Carolina, between 2000 to 2021—or those used for meat—were assessed in the study. In total, 12 species were studied, including a bearded seal.

Scientists already know that plastic pollution is a major risk to the ocean's wildlife, but the new study suggests that when ingested, microplastics can travel through the digestive tract and get lodged in tissues along the way.

Three kinds of fats plus lungs were assessed—plastics were found in all four tissues.

"This is an extra burden on top of everything else they face: climate change, pollution, noise, and now they're not only ingesting plastic and contending with the big pieces in their stomachs, they're also being internalized," Greg Merrill Jr., a fifth-year graduate student at the Duke University Marine Lab, said in a press release. "Some proportion of their mass is now plastic."

It is not yet certain what effect the plastic will have on the animals, but it is possible it affects hormones and endocrines.

The study said the plastics potentially act as a hormone mimics, and disrupt the endocrine glands.

Plastics are lipophilic, meaning they are attracted to fats. This could be the reason why they became easily lodged in the whale's fat.

The plastic measured from 198 microns to 537 microns, the study reported. To get an idea of its size, the study reported that a human hair is about 100 microns in diameter.

"Now that we know plastic is in these tissues, we're looking at what the metabolic impact might be," Merrill said in the release.

To continue his research, Merrill will run toxicology tests on the plastic.

"We haven't done the math, but most of the microplastics probably do pass through the gut and get defecated. But some proportion of it is ending up in the animals' tissues," Merrill said. "For me, this just underscores the ubiquity of ocean plastics and the scale of this problem. Some of these samples date back to 2001. Like, this has been happening for at least 20 years."

The findings support a Nature Communications study published in 2022 that said a blue whale could be swallowing 95 pounds of plastic waste per day in the Pacific Ocean off California.

According to the National Oceanic and Atmospheric Administration, about 8 million metric tons of plastic is estimated to have entered the ocean in 2010.

The plastic has serious effects on marine life. If ingested, it can cause animals to starve as they are full of plastic. Wildlife can also choke on plastic, which can strangle the animal when it becomes trapped around their neck.

The most common type of plastic found in the tissues was polyester fibers, which are commonly found as a byproduct of laundry machines, the new study reported.

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