Dolphins have become a common subject in pollution research because they’re found around the world, including in heavily-populated coastal areas. Photo / Gabriella Angotti-Jones, The New York Times
Dolphins have become a common subject in pollution research because they’re found around the world, including in heavily-populated coastal areas. Photo / Gabriella Angotti-Jones, The New York Times
Researchers studying bottlenose dolphins found polyester and other plastics in every animal they tested.
Scientists have found plastic pollution almost everywhere they have looked. In clouds. On Mt Everest. In Arctic snow.
Now, for the first time, tiny plastic particles have been detected in the breath of dolphins.
The findings,published Wednesday in the peer-reviewed journal PLOS One, point to the ubiquity of plastic waste in the environment. Each year, nearly two million tonnes of plastic end up in the world’s oceans.
Plastic also floats in the air, and the new study suggests that inhalation may be a significant way dolphins and other marine mammals are exposed to tiny plastic particles, called microplastics. Those particles, which are formed when plastic breaks down, have been linked to inflammation and cell damage, and can contain harmful chemicals.
“This really highlights how polluting plastic is,” said Leslie B. Hart, co-director of the Centre for Coastal Environmental and Human Health at the College of Charleston, in South Carolina, who led the research. “We have plastic everywhere. There’s really no safe place to get away from it.”
Other animals are known to breathe in plastics, though research is still sparse. Last year, scientists in Japan detected microplastics in the lungs of wild birds there. And researchers have estimated that people can inhale or ingest more than 100,000 microplastic particles a year from the food and water they consume, and from the air they breathe.
But dolphins have become a common subject of pollution research because they’re found around the world, including in heavily populated coastal areas. That makes them bellwethers of exposure to pollution and other environmental hazards.
For the latest study, Hart and Miranda K. Dziobak, a biochemist at the College of Charleston, collected samples of exhaled breath from 11 bottlenose dolphins in Sarasota Bay, Florida, and Barataria Bay, Louisiana. They partnered with the Brookfield Zoo Chicago’s dolphin research programme, which conducts catch-and-release health studies on dolphins. To capture the air samples, they held a petri dish just above each dolphin’s blowhole as it exhaled.
The researchers were trying to solve a mystery. In previous studies, they’d detected phthalates, chemicals used in plastic that are known to be endocrine disrupters that can harm human health, in dolphins in Sarasota Bay at levels considerably higher than those found in humans. Plastic pollution was a possible source.
Their analysis detected microplastic particles in the breath of all the dolphins they tested. The particles included several types of plastic polymers, like polyethylene terephthalate, known as PET, as well as polyester, one of the most common polymers used in clothes.
“When you do laundry, your clothes release millions of tiny plastic fibres,” Dziobak said. “And the tricky thing with those is that they’re so small, they’re so light, they can travel really easily in the water, in the air.”
Researchers sampled dolphin breath as part of their research. Photo / Todd Speakman/National Marine Mammal Foundation; MMPA/ESA Permit No. 18786-03 via The New York Times
The dolphins are then exposed to those plastic fibres. “The dolphins are breathing at the surface. They’re breathing in the airborne plastics,” Hart said. Researchers also think plastic particles in the water are being dispersed into the air by waves, she said.
Shannon Gowans, professor of marine science at Eckerd College in St. Petersburg, Florida, and head of the Dolphin Project there, who was not involved in the study, called the findings concerning. This was particularly the case, she said, after extreme storms like the hurricanes that just swept across Florida, overwhelming wastewater treatment plants and sending untreated water into the sea.
“The double whammy of the storm is that there was also so much debris that got carried away by the storm surge or went down the storm drains,” she said. “That’s all out in the waterways now. We’re going to see a spike in microplastics in the area.”
The College of Charleston researchers said they would focus their next research project on the specific health harms that microplastics could be causing in dolphins.
Dolphins hold their breath to chase prey underwater and have large lung capacity, Hart said. “Because of that, we think that perhaps they are taking in higher doses of airborne microplastics than, say, a human,” she said.
So what can ordinary people do to help? Reducing the amount of plastic you use and dispose of is a start, Dziobak said. It’s also a good idea to wear your clothes one extra time before washing them, or using a cold cycle because plastic fibres tend to shed more easily in hot water.
“Even something simple can make a difference,” Dziobak said.
