It rains microplastics on US parks, a thousand tons a year – Terra & Poli


Literally more than a thousand tons of microplastics per year, the equivalent of 123 million bottles, rain on the national parks and protected natural areas of the western United States. It is the alarming data that emerges from a study by the University of Utah: published in the journal Science, it shows that microplastics are transported from the atmosphere and move between sea, earth and sky following the best-known water cycle.

The researchers, coordinated by Janice Brahney, analyzed the sampled atmospheric particulate matter over 14 months in 11 national parks and protected areas. Faced with the first results “we were shocked and repeatedly made the calculations to find out if they were wrong,” confesses Brahney. “We thus verified that about 4% of the atmospheric particles from these remote locations were synthetic polymers.” And the estimates, the researchers admit, may even be wrong by default: the study has in fact considered only the colored particles and not the white ones that are more difficult to visualize.

Microplastics found in the atmosphere (source: Janice Brahney, Utah State University)

Most of the microplastics analyzed are microfibres deriving from industrial fabrics and materials. About 30% of the particles are brightly colored microspheres: made of acrylic, they probably come from industrial paints and coatings. Other particles are fragments of larger plastic pieces. The microplastics that deposit with atmospheric precipitations have cities and inhabited centers as their primary source, but secondary sources have also been identified which include the redistribution of the particles reintroduced from the soil and the surface of the waters. The particles that fall to the ground only due to the effect of gravity, on the other hand, indicate the existence of a large-scale transport mechanism, even intercontinental.


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