Flying insects are contaminating new environments by eating microplastics in polluted waters and carrying them through the air, a new study has found.
UK researchers found that microplastics -- pieces of plastic less than 5 millimeters in size -- remain in the bodies of mosquitoes and other waterborne insects even after they become flying adults.
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The findings mean that pollution from plastics being dumped into our oceans is being carried into the air, and raises concerns that birds and other creatures that eat the insects are also being contaminated.
The team from the University of Reading in England and Queen's University in Belfast, Northern Ireland, inserted two minuscule pieces of polystyrene, each weighing just over one gram per cubic centimeter, into young mosquitoes and observed the insects throughout their life cycles.
They found that the particles did not disappear from the mosquitoes' systems after the insects moved between life stages and started to fly, and were present inside the fully formed insects.
"The transfer of microplastics to the adults represents a potential aerial pathway to contamination of new environments," the authors wrote in the study.
"Thus, any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems," they added, using an abbreviation for microplastics. Freshwater insects such as mosquitoes are eaten by birds, amphibians, insects and fish, according to the Environmental Protection Agency in the United States.
More than 150 million tons of plastic are floating in the world's oceans, with an additional eight million tons entering every year, according to the World Economic Forum.
Plastic can entangle or be ingested by fish, birds and marine mammals, and can damage marine ecosystems such as coral reefs.
"This disturbing study raises real concerns about the prevalence of plastic pollution: it really is present everywhere, not just the marine environment," said plastic pollution campaigner Emma Priestland from the charity Friends of the Earth.
"Knowing that plastic can be transferred from the larval stage to the adult mosquito, which then serves as food to a multitude of larger animals, highlights the urgency with which we need to drastically reduce our plastic consumption," Priestland added.
A study from 2015 estimated that the total amount of floating plastic in the oceans could triple by 2025.