Microplastics detected in dolphin breath

U.S. researchers have detected microplastic particles in air exhaled by wild bottlenose dolphins, suggesting that inhalation may be a relevant route of exposure to these potentially harmful contaminants. Miranda Dziobak of the College of Charleston in South Carolina, U.S., and colleagues present these findings in the open-access journal PLOS ONE on October 16, 2024.

Around the world, humans and numerous other animals are exposed to tiny particles of plastic contaminants known as microplastics. In humans and rodents, microplastic exposure has been linked to adverse health impacts, such as oxidative stress and inflammation. Ingestion of foods contaminated with microplastics is a major route of exposure for both humans and wildlife, and inhalation of airborne microplastics has been linked to adverse health effects in humans.

However, few studies have examined inhalation as a potential route of microplastic exposure for wildlife. Now, this research team has collected samples of exhaled air from five bottlenose dolphins in Sarasota Bay, Florida, and six bottlenose dolphins in Barataria Bay, Louisiana during catch-and-release health assessment studies. To capture the air, they held a collection surface over or just above each dolphin’s blowhole as it exhaled.

Analysis of the collected air showed that all 11 dolphins had at least one suspected microplastic particle in their breath. Further analysis of the exhaled microplastic particles showed that they included both fibers and fragments and included several types of plastic polymers, including polyethylene terephthalate (PET), polyester, polyamide, polybutylene terephthalate, and poly(methyl methacrylate), also known as PMMA.

For comparison, the research team had also sampled the surrounding air near the dolphins, allowing them to confirm that the detected microplastics were not just airborne near the blowholes but were actually exhaled.

These results support the idea that inhalation could be another key route of microplastic exposure for dolphins, alongside ingestion. However, the authors note that their findings are preliminary, and that further research will be needed to better quantify the degree of inhalation exposure to various types of microplastics among bottlenose dolphins, as well as to determine the potential impacts on dolphins’ health, such as the possibility of lung damage.

The authors add: “We know that microplastics are floating around in the air, so we suspected that we would find microplastics in breath samples. 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.”

#####

Author Interview: https://plos.io/3Nh6GrK

In your coverage please use this URL to provide access to the freely available article in PLOS ONE: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0309377

Citation: Dziobak MK, Fahlman A, Wells RS, Takeshita R, Smith C, Gray A, et al. (2024) First evidence of microplastic inhalation among free-ranging small cetaceans. PLoS ONE 19(10): e0309377. https://doi.org/10.1371/journal.pone.0309377

Author Countries: USA, Sweden

Funding: Research reported in this publication was supported by the National Institute of Environmental Health Sciences of the National Institutes of Health under Award Number R15ES034169 [LH]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Sarasota Bay health assessments were funded primarily by Dolphin Quest, Inc. AF was funded by Fundacion Oceanografic and Global Diving Research SL. Barataria Bay health assessments were funded primarily by a Strategic Environmental Research and Development Program grant (no. RC20-1097), with contributions from the Gulf of Mexico Research Initiative and the National Marine Mammal Foundation [CRS, RT].