We know about acidic rains. We have heard of fish that rain from the sky. If we thought nothing could surprise us, we were wrong. Plastics, or more precisely microplastics, began to rain from the sky as well. What is the cause? And what are the microplastics?

Colorado’s National Park Rain Samples

The U.S. Geological Survey researcher, Greg Wetherbee, accidentally found the presence of plastics in rain samples while he was he was looking for fragments of metals or coal, particles that might indicate the source of airborne nitrogen pollution in Rocky Mountain National Park. He collected the samples from eight sites along Colorado’s Front Range. In 90 percent of the samples, Wetherbee found a rainbow wheel of plastics, mostly fibers and mostly colored blue. He also found other shapes, like beads and shards. The plastics were tiny, needing magnification of 20 to 40 times to be visible under a microscope and they were not dense enough to be weighed. More fibers were found in urban sites, but plastics were also spotted in samples from a site at elevation 10,300 feet in Rocky Mountain National Park.

The theories of the Appearance of Plastics in the Rain

Austin Baldwin, a USGS hydrologist who studies microplastics, told Circle of Blue, that plastic pollution is ubiquitous. It’s just the tip of a glacier of deeper problem. Baldwin presented several theories for the source of microplastics in Colorado – on of the sources could be laundry water, or clothes dryers which could be venting a waste stream into the air. Fibers sent to a wastewater treatment plant could end up in the sludge that is then spread on farm fields for fertilizer. As the sludge dries, the fibers could be lifted into the air. Another possible source could be the slow degradation of car tires.

Microplastics versus Natural Fibers

Microplastics is a generic term used for a variety of plastic fragments ranging from 100 nanometers to 5 millimeters that occur in water, soil and air as part of their contamination. It is a mixture of fibers, spheres or fragments of irregular shape, part of which is intentionally produced in such a form (primary microplastics), but most arise from the gradual breaking, fragmentation of larger pieces of plastic (secondary microplastics). These micro-plastics eventually accumulate in the oceans (often at the bottom), where they seriously threaten the environment.

However, according to the meta-analysis from 2018, published in the journal Environmental Toxicology and Chemistry, there is not yet sufficient evidence that this is threatening or threatening the environment. In addition, for example, natural fibers are found in water more often than man-made fibers, but both are associated with certain risks.

Source: ecowatch.com/plastics-in-rain-colorado-2637876643.html, phys.org/news/2018-10-impact-microplastics-environment-unclear.html, wikipedia.org, circleofblue.org/2019/world/its-raining-plastic-researchers-find-microscopic-fibers-in-colorado-rain-samples/

Credit: whoi.edu, Pixabay.com