‘Plastic Rain’ Litters Remote Western Wilderness
Researchers are shocked at the volume of tiny bits and beads falling from the sky like dust and rain
There was a backwoods saying I heard as a kid, a sad joke about the human propensity to litter even remote locations: No matter where you go, a beer can will beat you there. Add airborne plastic bits to that list.
Plastic particles that had wafted through the atmosphere and fell out in wind and precipitation, year-round, were found in ground samples collected from 11 remote locations in national parks and wilderness areas across the western United States. More than 1,000 tons of microplastics, all materials that are made by humans and don’t occur naturally, fall on these protected lands each year, the scientists say, equal to at least 123 million plastic water bottles.
That estimate is just for the wilderness areas and parks that were studied, which make up only a fraction of land in the country. There’s no reason to assume plastics aren’t raining down all over the nation and around the world.
“No place is safe from plastic pollution,” the scientists write in the June 12 issue of the journal Science.
“I think we could expect higher deposition rates within population centers,” study leader Janice Brahney, PhD, an assistant professor of watershed sciences at Utah State University, tells me. “We really don’t know as much as we would like at this point about where we might expect deposition rates to be the highest.”
The finding may not be unexpected, but the scope of the “plastic rain,” as Brahney and her colleagues call it, is surprising.
“We were shocked at the estimated deposition rates and kept trying to figure out where our calculations went wrong,” Brahney said. “We then confirmed through 32 different particle scans that roughly 4% of the atmospheric particles analyzed from these remote locations were synthetic polymers.”
Microplastics, the size of dust particles have been found in water throughout the world and on land, but little is known about the origins, or about how far and wide the bits travel. The assumption now is that tiny pieces of plastic are circling the globe, just as water and natural dust do. In a nutshell, plastic is everywhere.
“Our data show the plastic cycle is reminiscent of the global water cycle, having atmospheric, oceanic, and terrestrial lifetimes,” Brahney said. “Microplastics are less dense than soil and therefore might travel longer distances than natural dust particles,” other researches write in a related perspective in the journal.
Most of the plastics were microfibers used to make clothes and industrial materials. About 30% were bright microbeads thought to come from industrial paints and coatings.
Smaller plastic particles, too tiny to be detected by the researchers’ microscopes, are likely present, too, Brahney said by email. And she notes that some of the finest plastic particles are known to lodge in people’s lungs.
Other research has found we’re constantly breathing and drinking microplastics that simply did not exist a century ago, before plastic production became widespread. There’s other evidence that microplastics can harm aquatic organisms that can in turn disrupt life on up the food chain. Plants, too, can be harmed by microplastics, according to a recent study in the journal Global Change Biology.
“There is also some evidence that plastics can affect soil temperatures and moisture-holding capacity,” Brahney said in an email. “So this raises a lot of new questions about the long-term impacts of plastic accumulation in sensitive ecosystems.”