In the waters off Florida and Louisiana, bottlenose dolphins are exhaling more than just spent air. They are breathing out microplastic particles — tiny bits of plastic pollution that have become a pervasive threat to marine life. Researchers from the College of Charleston in South Carolina note this is the first time these particles have been detected in dolphin breath.
The discovery suggests that inhalation, long overlooked, might be a significant way that dolphins — and potentially other marine animals — are exposed to microplastics.
“We are concerned by what we are seeing because dolphins have a large lung capacity and take really deep breaths, so we are worried about what these plastics could be doing to their lungs,” said Miranda Dziobak, lead author of the study.
Breathing Plastic: A New Route of Exposure
Microplastics — tiny fragments of degraded plastic waste — have infiltrated ecosystems across the globe. From fish to birds to humans (in faeces and even in our blood), these particles have been linked to health risks like oxidative stress and inflammation.
Until now, most research has focused on ingestion as the primary route of exposure, especially in humans and animals that inadvertently consume microplastic-contaminated food. However, in this study, researchers zeroed in on inhalation, a route that has received far less attention in wildlife.
Dziobak’s team gathered exhaled air samples from 11 bottlenose dolphins in Sarasota Bay, Florida, and Barataria Bay, Louisiana. As the dolphins surfaced, a collection device hovered above their blowholes, capturing the air they expelled. The result was startling: all of the dolphins had at least one suspected microplastic particle in their breath. These particles were not just stray pollutants from the environment. Comparison samples from the surrounding air ruled that out. The microplastics were truly being exhaled.
Analysis revealed that the particles included a mix of fibers and fragments made from various plastic polymers like polyethylene terephthalate (PET), polyester, and polymethyl methacrylate (PMMA). These materials are common in consumer goods like textiles and packaging, which often end up breaking down into microscopic pieces.
What It Means for Dolphins — and Us
The idea that dolphins are inhaling microplastics raises troubling questions about the potential health effects.
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“We know that microplastics are floating around in the air, so we suspected that we would find microplastics in breath samples,” said Dziobak.
But confirming their presence in the respiratory system of marine mammals raises new concerns, particularly about lung health. Dolphins are deep divers with large lung capacities. This leaves them more susceptible to inhaling these particles as they take deep breaths.
The study’s findings are preliminary, and the research team emphasizes that more work is needed to understand the full extent of microplastic exposure through inhalation. The next steps involve quantifying how much plastic dolphins may be inhaling and determining whether it could be damaging their lungs.
For now, the discovery adds another layer to the growing body of evidence that microplastics are everywhere — in the oceans, on land, and even in the air we breathe. It’s not just dolphins at risk. Research has already shown that humans are inhaling airborne microplastics, too, with potential health impacts still largely unknown.
The findings appeared in the journal PLOS ONE .