Plastic pollution doesn't just pollute the world's oceans. It's also in the air we breathe, travel in the wind, and drift down from the sky, according to a new study. In the American West alone, more than 1,000 tons of tiny fragments rain down national parks and wilderness areas each year, which corresponds to a value between 123 and 300 million plastic bottles.
"There is no corner of the earth's surface where there is no microplastics," said Janice Brahney, a Utah State University scientist who is the lead author of the new study. "It's really annoying to think about it."
While the disruptive presence of plastics in landfills, in the oceans, and in freshwater environments such as the Great Lakes is known, research into airborne particles is more recent. Earlier publications described how airborne microplastics can be found in Europe, China and the Arctic, among others.
The new paper, published in Science magazine on Thursday, reports that plastic was found in remote parts of the United States. The researchers collected samples from 11 national parks and wilderness areas.
They found tiny pieces of plastic in 98 percent of the 339 samples collected. Plastics made up 4 percent of the dust particles tested.
It was a very surprising result to find so much plastic in supposedly untouched areas, said Dr. Brahney. She and her colleagues kept coming back to their calculations, she said, assuming they were wrong. But they weren't.
The collections were created both under dry conditions and during rainy and snowy periods, which Dr. Brahney and co-authors Margaret Hallerud and Eric Heim from Utah, Maura Hahnenberger from Salt Lake Community College and Suja Sukumaran from Thermo Fisher Scientific. Determine the probable origin of the particles. Larger particles came down with rain and snow, while smaller ones appeared under dry conditions.
The researchers concluded that the particles deposited in wet weather are likely to be up close, with the plastic parts being blown into the air by storms from urban centers and then falling again with rain and snow. In contrast, the smaller, lighter particles, they suggested, had traveled extremely long distances with high currents in the atmosphere and had become part of the cycles of global dust transport. The dry deposits made up more than 75 percent of the plastic tested.
The microfibers collected by the researchers matched the textiles used to manufacture clothing, carpets and industrial coatings, as well as outdoor equipment such as tents and waterproof clothing. This means that "emissions from park users can contribute to the observed deposition rates, especially in national parks with high visitor rates", although the researchers concluded that these sources did not produce a large proportion of the total samples.
Chelsea M. Rochman, an assistant professor of ecology at the University of Toronto, who co-authored an accompanying comment on the new study, said in an interview that the paper was not the first to show microplastics in atmospheric or even atmospheric deposition from Microplastics to distant places. But she added that the researchers appeared to be the first to ask through their research: "The basic scientific question: why and how does this happen?"
The comment says that the idea of "plastic in the rain" is a discovery that can "strain your imagination".
Dr. Brahney added that the phenomenon could contribute to environmental disruption in microbial communities and cause greater ecological damage. People could also be at risk, she said; The presence of so many fine particles in the air means "we breathe it too". The health effects of ingesting plastic particles are not known, although the size of the detected particles matches the size of those that accumulate in the lung tissue, she said.
Previous studies on exposure to high levels of inhaled plastic particles in the workplace have linked them to lung disease and tissue damage. The outdoor plastic concentrations are lower, but can contribute to the effects of particles.
Stephanie Wright, a lecturer in environmental toxicology at King’s College London, who examined the effects of inhaled microplastics on health, said that in the atmosphere “these concentrations are still trace amounts compared to other prominent particles such as the soot contained in them are “everyday soot. "Until we have a solid understanding of our exposure, it is difficult to infer health effects," she said.
Joana C. Prata, Ph.D. The student in biology and ecology of global change at the University of Aveiro in Portugal, who also examined the health risks of plastics in the air, said that the newly discussed plastics in the air could already contribute to the negative health effects of pollution and that "adverse effects of a chronic exposure to low concentrations of microplastics in the air can not be excluded. "
Dr. Rochman, the author of the commentary, said that new research and our growing awareness of the amounts of plastic that are falling all around us have led to the question, "What are you doing with it?"
The paper gave a kind of answer, but not an easy one. “The consequences for ecosystems are not yet exactly known, but they will be inevitable in the near future. If the potential dangers of microplastics in the environment are to be reduced, ”the authors wrote, nothing less than“ the commitment of the global community ”is required.