Researchers find plastic in raindrops
Aug 18, 2019 10:39AM
● By Editor
By Mark Torregrossa of mlive.com - August 16, 2019
Researchers have discovered that plastic is falling with the raindrops and snow.
Researchers at the United States Geological Survey (USGS) have been collecting rainfall for four decades as part of the National Atmospheric Deposition Program. One of the goals of collecting the rain was to track nitrogen levels in the precipitation.
But a surprising discovery occurred during the routine research.
Gregory Wetherbee, research chemist at the USGS, was trying to trace the origin of nitrogen in the rain in Colorado. To trace where the nitrogen was coming from, the USGS checks other elements in the rain. A filter on the testing machine could indicate the origin of the nitrogen, but a desired test on the filter would ruin the filter. So before the filter test, Wetherbee put the filter under a microscope. That’s when he discovered red, blue, green and purple fibers on the filter.
That’s when he discovered plastic fibers in Colorado rain.
The USGS has 250 rain collection sites around the country. The rain collectors only gather precipitation when it’s falling. Wetherbee says these rain samples don’t contain any pollutants just blowing around in dry air.
Wetherbee found many different colored plastic fibers on the filters that the rain sample had been run through. He also says there was an occasional particle of plastic in the rainwater.
A string of rain collecting sites stretch from the Denver and Boulder urban areas northwest to very remote areas in the Rocky Mountains. Wetherbee thought they would find the plastic blew into the rain from the urban areas of Denver and Boulder. There is a weather pattern that develops on easterly winds east of Denver. The air is blown westward on east winds, and shoved up the mountains. The forcing of air up the Rockies produces rainfall. This is where Wetherbee thought the plastic would originate. This wasn’t always the case. He found just as much plastic in the remote Rocky Mountain sites west of Denver, with rainfall blown in from the west.
Wetherbee figures the plastic fibers are blown off the ground and picked up into the atmospheric currents. Eventually those plastic fibers get caught in a raindrop and fall to the ground.
The presence of plastic in remote areas of the Rocky Mountains means plastics might be coming from a long distance to the west.
In fact, Wetherbee points out a European study just released two days ago found microplastics in the Arctic.
The plastics Wetherbee found were mostly fiber-like and not able to be seen by the naked eye. He did find one plastic bead in 300 samples.
Wetherbee says researchers at the USGS don’t know where the plastic exactly comes from. There are no identifying characteristics to the plastic.
Wetherbee states the USGS wants the public to be informed about the environment. Wetherbee says, “There’s more plastic pollution than what meets the eye.”
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