Whales Are Ingesting a Shocking Amount of Microplastics

The ocean is home to more than 200,000 known species and as many as 2 million that we have yet to discover. And, on a dire note, it is also home to 24.4 trillion pieces of microplastics. In 2022, researchers spotlighted how bad marine microplastic pollution is getting: The total amount of microplastics deposited on the bottom of oceans has tripled in the past two decades.

But microplastic particles don't just end up at the bottom of the ocean. Animals are eating them—at least 1500 species have been reported to ingest plastic. And a lot of it.

For example, whales in New Zealand's Hauraki Gulf consume roughly three million microplastics daily, according to research published in the journal Science of the Total Environment, which analyzed whale feces to see how much microplastics were present.

Other research has even more troubling conclusions. A Nature Communications study found that blue whales may swallow 10 million microplastic pieces daily.

A Diet of Man-Made Materials

Shirel R. Kahane-Rapport, the lead author of the Nature Communications study, tells Treehugger her team was surprised by the quantity of microplastic ingestion and the source of the risk.

"Even in the moderately polluted waters off the U.S. West Coast, baleen whales may still be ingesting millions of microplastics and microfibers per day," says Kahane-Rapport. "The vast majority (99%) is via their prey that has previously ingested plastic and not from the water they filter."

"Understanding ingestion rates is the first step toward understanding the health effects of microplastic on whales," Kahane-Rapport adds.

When we think of marine animals ingesting plastic, we may think of them mistaking it for food and maybe even passing it through their system. But microplastics are much more insidious than that.

"Other research has shown that if plastics are small enough, they can cross the gut wall and get into internal organs though the long-term effects are still unclear. Plastics can also release chemicals that are endocrine disruptors," says Kahane-Rapport. "This is concerning, and while we do not yet understand the long-term health effects, it is likely not a good sign for these organisms and their prey to ingest a man-made material like plastic."

Further-Reaching Impact

This is obviously bad for whales, but it also has implications for humans and the ocean at large. We are also part of these food chains and are consuming microplastics regularly. They are in our bottled water, in our table salt—they are even in our house dust and in the air we breathe. And we still don't know what the health effects are.

Meanwhile, the impact on whales—and what it signifies—is troubling on many fronts.

"Whales are ecosystem engineers," says Kahane-Rapport. "They can act like a pump, recirculating the nutrients that they consumed ... and they can serve as ecosystem sentinels—when whales are not thriving, other parts of the system are likely suffering."

What's Next?

Microplastics are created in vast numbers by seemingly mundane everyday activities like doing laundry, where synthetic fibers are rinsed into the wastewater. Or driving, where plastic from tires generates more microplastic waste than any other source, according to researchers.

Kahane-Rapport gives us some suggestions on steps that individuals can take:

• Dispose of waste properly so it doesn’t end up in the sewer
• Add a simple filter to your washing machine to catch microfibers
• Advocate for better wastewater treatment (that prevents microplastic from entering the water system) in your city
• Speak to your local council people, and politicians can help bring about larger change
• Put pressure on large corporations to dispose of their waste responsibly!

[And Treehugger has more excellent tips here: 9 Ways to Combat Microplastics at Home.]

As for the whales, Kahane-Rapport says there is more research needed. "The next research step will be to determine how much plastic the whales egest (poop out) and how much they retain in their bodies. Following that, it would be very interesting (and complicated) to determine the direct health effects on their tissues."

As the study concludes, "For species struggling to recover from historical whaling alongside other anthropogenic pressures, our findings suggest that the cumulative impacts of multiple stressors require further attention."