It’s Raining Plastic, Researchers Say

While the pandemic has triggered a spike in plastic pollution, researchers have just made another very unsettling discovery. In a study published on June 11 in the journal Science, researchers have found that over 1,000 metric tons of microplastics—equivalent to a whopping 120 million plastic water bottles—fall on just 11 protected areas in the U.S. annually. While we’ve known for a while that microplastics are being blown by the wind to supposedly pristine places—from the Arctic to the remote French Pyrenees—the new study confirms that the American West and presumably the rest of the world is receiving “plastic rain”.

“There’s no nook or cranny on the surface of the earth that won’t have microplastics,” said Janice Brahney, a Utah State University scientist who is the lead author on the new study. “It’s really unnerving to think about it.” Brahney had initially planned to investigate how dust carried nutrients. But when she saw colourful fibres and beads caught among dust, she decided to study the transmission of microplastics.

As the plastics discarded by humans break down into tiny pieces in the environment, they, too, drift through the atmosphere. To collect the samples, the researchers used a pair of 13.2 litre buckets with a sensor triggering lid, segregating the plastic into wet plastic and dry plastic, based on their medium of transmission. Once collected, they counted the plastic particles by hand under a microscope through visual cues such as vivid colours and unnatural textures—a characteristic of plastic— to distinguish the plastic from the dust.

The particles and fibers they captured originated from various sources—such as paint, cosmetic products and carpeting. Disturbingly though, the largest contribution came from clothing—clothes shed microfibers frequently not only when they're being washed and dried but also when in daily use. Brahney’s team found that wet microplastics most likely originated in larger urban areas, while dry microplastics travelled longer distances, often across continents.

Since their discovery in oceans in the 1970s, microplastics—which are fragments from larger pieces of plastic—have been found to be as large as a grain of rice or smaller than a particle of dust. Since plastic isn’t biodegradable, it ends up in waste piles or landfills, and then breaks down into microparticles. It then makes their way through the Earth’s atmosphere, soil, and water systems. They have been found nearly everywhere researchers have looked—not just in heavily populated cities but also on remote mountaintops. While it has been assumed that their presence in areas distant from human habitation is because they are carried by winds, Brahney’s study is one of the first to directly investigate the possibility.

“Learning about plastics and how they don’t decompose and degrade it seems like, ‘Oh my gosh, we should’ve been expecting this, they’re just fragmenting into these tiny sizes they could certainly be carried by the wind,’” said Brahney to The Guardian. “We’ve just been missing it.”

Although their full effects on the human body are still unknown, scientists are starting to raise health concerns over these particles. A study in 2019 concluded that the average person inhaled up to 11 microplastics per hour. They’re small enough to lodge into lung tissue, and can lead to asthma, and even cancer. Added Brahney, “We’re only starting to really scratch the surface of what is in the atmosphere and how it's moving around."

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