‘It is raining plastic’: USGS finds microplastics in 90 percent of Colorado rainwater samples

Rainwater found to contain microplastics, according to report from USGS

Microplastics have made their way into our food, water and bodies, and now the tiny plastic particles are literally raining down on us.

RESTON, Va. - Microplastics are microscopic pieces of plastic that are making their way into everything from drinking water to marine life, and now the U.S. Geological Survey says they’re falling from the sky when it rains, according to a new report.

Scientists collected samples of rainwater from a variety of locations throughout Colorado, some from urban areas and others from remote areas, and found plastic in more than 90 percent of the samples.

Most of the plastic which was found in the samples consisted of fibers which needed to be magnified 20 to 40 times to be visible. Blue was the most common color of these particles, followed by red, silver, purple, green and yellow.

Atmospheric wet deposition samples were collected at eight different sites, most of which were along the Denver and Boulder urban corridor. Two of the sites were more remote, one of which was located at Loch Vale in Rocky Mountain National Park.

Samples were collected in buckets before being sent to the NADP Central Analytical Laboratory, where they were run through a .45 micrometer filter to separate any particulate matter from the water. The filters were then dried and analyzed under a binocular microscope that was fitted with a digital camera.

More plastic was found to be contained in samples pulled from urban locations than from remote locations, but the frequent presence of plastics in the Loch Vale site samples suggests that “wet deposition of plastic is ubiquitous and not just an urban condition,” the report says.

The implications of these finding are not fully known, and the report states that more research will need to be done with better sampling, identification and quantification methods — in large part because the study was not designed for collecting and analyzing samples for the presence of plastic particles.

“The results are unanticipated and opportune,” the report says.It’s too early to say for certain how these plastics are accumulating and being assimilated in the environment and in living organisms, and more research needs to be done to determine the long term impact of microplastic-contaminated rainwater.