Mosquito larvae in bodies of water contaminated with plastic ingest microplastics that they can then pass up into the food chain, findings of a new study revealed.
Microplastic pollution has raised concerns as tiny plastic particles show up in more places. Microplastics have been discovered in tap water around the world, in oceans, and even in remote areas such as the Swiss mountains.
These particles may leach toxic chemicals and even harbor bacteria. Research also revealed that ingestion of microplastics, or plastic particles that are smaller than 5 mm, can compromise the health of animals, particularly marine creatures that ingest them.
In the new study published in the journal Biology Letters, Amanda Callaghan, from the University of Reading in the United Kingdom, and colleagues fed a mixture of microplastics and food to mosquito larvae that live in water.
Culex pipiens mosquitoes were used for the study because the species is found across the world and in many habitats.
The study revealed that mosquitoes could serve as a vehicle that transports plastic into uncontaminated environments. The researchers found that mosquito larvae readily consumed tiny fluorescent microplastic particles and that these particles remained inside the insects even as they transformed into flying adults.
Callaghan explained to The Guardian that the larvae eat algae that are about the same size as microplastic, which explains why they cannot set apart the plastic particles from their food.
“Larvae are filter feeders that waft little combs towards their mouths, so they can’t actually distinguish between a bit of plastic and a bit of food,” Callaghan said.
Callaghan said that the findings show that mosquitoes may serve as a vector for transferring microplastic from water sources into the guts of birds and bats that feed on insects.
It isn’t just mosquitoes that are ingesting and retaining microplastic in their body. The researchers said that it is highly likely that other flying insects that started as water larvae also eat and retain these plastic particles.
“We were just looking at mosquitoes as an example but there are lots of insects that live in water and have the same life-cycle with larvae that eat things in water and then emerge as adults,” Callaghan said. “Any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems.”
Birds, bats, and spiders are among the species that eat large amounts of insects, which means they are also consuming microplastics. Experts also think that humans consume microplastic.
“The transfer of MPs to the adults represents a potential aerial pathway to contamination of new environments,” the researchers wrote in their study, which was published on Sept. 19.