In a new study, scientists in the US detected microplastic particles in air exhaled by bottlenose dolphins.
The discovery suggests that these tiny, harmful plastic fragments can be inhaled, as well as ingested.
The findings, led by Miranda Dziobak from the College of Charleston in South Carolina, were published in PLOS ONE.
Around the globe, humans and animals alike are exposed to microplastics, with research linking their presence to harmful health effects such as inflammation and oxidative stress. While ingestion of plastic particles has been a well-documented issue in both wildlife and people, this new study highlights a less-explored path of exposure: inhalation.
During the study, the team collected exhaled air from 11 wild bottlenose dolphins in Sarasota Bay, Florida, and Barataria Bay, Louisiana, as part of ongoing health assessments. By holding a collection device over the dolphins' blowholes as they surfaced to breathe, the researchers captured samples for analysis.
What they found was striking – every dolphin exhaled at least one microplastic particle. These particles ranged from fibres to fragments and included common plastic polymers, such as polyethylene terephthalate (PET), polyester and polyamide, among others.
"Finding microplastics in the exhaled breath of dolphins highlights how extensive environmental microplastic pollution is"
To ensure that the microplastics were coming from the dolphins and not the surrounding environment, the team also sampled air near the blowholes, confirming that the detected particles were indeed exhaled by the animals.
"Finding microplastics in the exhaled breath of dolphins highlights how extensive environmental microplastic pollution is," says Dziobak. "Because of their large lung capacity and deep breaths, we are worried that breathing in microplastics may damage their lungs.
"Studies like this also warn us of hazardous exposures that people living and working in the coastal environment may be facing," adds Dziobak.
The discovery suggests that, alongside ingestion, inhalation could be another significant way dolphins are exposed to microplastics. However, the researchers emphasise that more studies are needed to determine the full extent of this exposure and its potential effects on dolphin health, such as respiratory damage.
Find out more about the study: First evidence of microplastic inhalation among free-ranging small cetaceans.
Bottlenose dolphin health assessments were conducted under MMPA/ESA Permit No. 18786-03 in 2018 and MMPA/ESA Permit No. 24359 in 2023, CC-BY 4.0
More wildlife stories from around the world
- Forest plants are being driven westwards through Europe at 3.56 kilometres a year
- Scientists just split open a 2-billion-year-old rock – what they found inside is truly astonishing
- Tiny 'backpacks' are being strapped to baby turtles on a remote island in the Great Barrier Reef. Here's why
- Ant queens cannibalise infected young to prevent deadly disease outbreak
