Harmful microplastics have been found in the breath of dolphins for the first time, most likely inhaled when the marine mammals come up out of the water for air.
A US research team, whose preliminary findings are published in the journal, Plos One, say they are concerned about the potential impact of inhaled plastics on the animals’ lungs.
The researchers relied on a method of catch and release and sampled the exhaled breath by holding a petri dish over their blowholes. Controls were used for air adjacent to the animals.
The scientists collected samples of exhaled air from bottlenose variety in two sites: Sarasota Bay, Florida, an urban estuary, and Barataria Bay, Louisiana, a rural site.
They found microplastics in the exhaled breath from all 11 bottlenose dolphins sampled, which means most likely the particles were airborne and carried on the wind – a process which has led to them even being found on the slopes of Mount Everest.
Many of the microplastics found in the dolphin breath samples were polyester, a common polymer used to make clothes, which shed huge amounts of particles when washed.
Leslie Hart, co-author of the study and public health expert at the College of Charleston University in South Carolina, said: ‘Microplastic inhalation in humans is a budding field, but there have been few studies in wildlife.
‘The fact that dolphins have a much larger lung capacity and are taking deep breaths may mean they are exposed to higher doses of microplastics than humans.’
Disaster for Dolphins
The researchers worked with the Sarasota dolphin research programme at Brookfield Zoo Chicago and the National Marine Mammal Foundation.
‘We are just starting to understand how dolphins are exposed to microplastics,’ said Hart, who has studied plastics in dolphins for a decade.
The researchers were particularly concerned about the potential impact on those in the Barataria Bay area because the cetaceans had already suffered poor pulmonary health due to the Deepwater Horizon oil spill disaster in 2010.
‘There is a potential that this could make problems worse,’ added Hart.
In humans microplastic particles have been linked to increased mortality from traumatic injury, silicosis, chronic obstructive pulmonary disease, and lung cancer.
Other conditions identified as being increased by the plastics are leukaemia, lymphoma, brain cancer, breast cancer, mesothelioma, decreased fertility and cardiovascular disease.