Microplastics can enter the food chain by mosquitoes

Researchers said Wednesday that mosquito larvae ingested microplastics that could be transported into the food chain, uncovering a new way in which polluting particles could damage the environment.

Microplastics – tiny plastic chips degraded from synthetic products, such as synthetic garments, car tires and contact lenses – cover a large part of the world's oceans.

Difficult to locate and harder to collect, they can seriously damage marine wildlife and pose a significant risk to human health as they cross the food web and contaminate water supplies.

Researchers at the University of Reading believe they have evidence for the first time that microplastics can enter our ecosystem by air via mosquitoes and other flying insects.

The team observed mosquito larvae ingesting microscopic plastic beads – similar to the tiny plastic beads found in everyday cosmetics – before monitoring them throughout their lifecycle.

They found that many particles were transferred into the adult form of mosquitoes, which meant that all creatures that ate flying insects in the wild also ingested plastic.

"The important thing is that this is probably very widespread," Amanda Callaghan, a biology researcher in Reading and lead author of the study, told AFP.

"We were just looking at the mosquitoes, but there are a lot of insects that live in the water and have the same life cycle as the larvae that eat things in the water and become adults."

Animals known to eat such insects include several species of birds, bats and spiders, all of which are hunted in turn by other animals.

"It's essentially another pollution path that has not been considered before," Callaghan said.

Although the team observed the mosquitoes under laboratory conditions, she said it was "very possible" that the process was already happening in nature.

Several countries, including Britain, banned products containing microbeads, but Callaghan said the scale of the problem was still being discovered.

"This is a major problem and the plastics already present in the environment will accompany us very, very long," she said.

The study is published in Letters of biology.

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More information:
Up and away: ontogenic transfer as an air dispersion pathway for microplastics, Letters of biology, rsbl.royalsocietypublishing.or … .1098 / rsbl.2018.0479