The particles of microplastic can spread in nature through mosquitoes. To such conclusions came the researchers from the University of Reading (Great Britain). In the course of their experiment it was found out that microscopic particles of plastic remained in the body of insects at all stages of their development – from the larva to the adult. And since they are included in the diet of birds and amphibians, the microplastic can easily move along the food chain and, according to experts, eventually end up in the human body. According to Russian scientists, the discovery of foreign colleagues indicates that the actual scale of microplastic propagation in the environment is much greater than previously thought.
The problem of environmental contamination with microplastics – particles of plastic less than 5 mm in size – takes on a global scale. Previously it was believed that the first link in the food chain, through which the microplastic “advances” to higher predators, is mainly water inhabitants. However, scientists from the British University of Reading have found out that microparticles can carry mosquitoes from reservoirs.
A new threat
The female mosquito of an ordinary lays on a surface of a reservoir for one time up to 200 eggs. The larvae hatched from them live in water, feeding on microorganisms and organic remains, among which there is a microplastic that is present in almost all water bodies.
The researchers were mainly interested in whether these particles remain in the mosquito’s body at various stages of its life cycle – from the larva to the adult (imago).
To answer this question, scientists conducted an experiment in which 150 larvae of an ordinary mosquito were placed in a container and filled it with water with microparticles of polystyrene – a polymer used in the production of disposable dishes, children’s toys, and also used as a facing material in construction. At the same time, another 150 mosquito larvae were placed in a vessel with a granulated granulated food for guinea pigs.
The diameter of the particles in both groups was from two to 15 micrometers (μm). To determine whether the granules remain in the mosquito, scientists have previously colored them with a fluorescent bright green paint.
After this, specialists observed the growth of larvae. At the pupal and adult stages, researchers selected 15 random insects from each group.
As a result, it was found that in the digestive tract of mosquitoes that were in the vessel with food, foreign particles were absent – both in the pupa and in the adult. In this case, insects living in containers with plastic, a completely different picture was observed: in larvae, scientists counted about 3 thousand particles with a diameter of 2 μm and 300 particles with a diameter of 15 μm, in imago – only about 40 particles of smaller size. However, according to the researchers, even such a relatively “modest” final result is statistically significant.
“It is likely that many other flying insects, whose life cycle includes the stage of the larva, are carriers of the microplastic. In addition, birds, bats and spiders that feed on mosquitoes are also likely to carry plastic particles, “study author Amanda Callaghan said.
Russian experts note that the results of the study may indicate a real scale of microplastic propagation in the environment.
“All the microscopic particles that are contained in the reservoir easily enter the body of the fish. Of course, if the microplastic is not removed from the body of the fauna that swallowed it, it is passed on further along the food chain. So, before scientists managed to find seabirds, in the body of which contained microplastic. Now in the risk group there were also terrestrial-tree feathers, which feed on insects, “- said in an interview with RT zoologist Olga Ezhova.
According to the director of the All-Russian Institute of Nature, Andrei Peshkov, plastic comes into the environment in the form of waste over the past 50 years. Disintegrating into small pieces, it contaminated practically all media in that short period of time: fresh water, land and its final point of “migration” – the World Ocean.
“Since the ocean is huge, at first the scale of the disaster was not noticeable. However, plastic eventually penetrates into all new environments, so now this anthropogenic impact isdifficult not to notice. In this case, mosquitoes are only one of the links in the food chain, through which the micro-plastic moves. Most of the plastic particles settle on the ocean floor – the habitat of the crustaceans, which are the primary food base for many species of fish, “Peshkov said.
According to the expert, it is extremely difficult to assess the consequences of microbiological contamination of the biosphere, since such studies have been conducted not so long ago. Peshkov believes that the main effort now is to focus on the development of measures that increase human responsibility in relation to the environment.
“It is necessary to develop a global” culture of purity “on a global scale. First of all, this concerns the United States, which today is the most massive polluter of the Earth and refuses to comply with the terms of international agreements on climate, “Peshkov summed up.