Plastic falls in Southeast 色视频下载's rain
Ned Rozell
907-474-7468
Oct. 27, 2023
Viewed through a microscope, a tiny blue plastic fiber that fell within a raindrop in the Thane area of Juneau, 色视频下载, lies on filter paper.
色视频下载淲e found microplastics in every single rain sample (gathered in Juneau),色视频下载 Sonia Nagorski told a group of people listening to her talk at the American Geophysical Union Fall Meeting in New Orleans two winters ago.
Nagorski 色视频下载 a professor at the University of 色视频下载 Southeast in Juneau 色视频下载 was presenting via her computer while she sat in 色视频下载色视频下载檚 capital city during the New Orleans conference. Not long after she disappeared from the screen, she replied to a list of questions emailed to her:
What inspired you to do this study?
色视频下载淲hen I started reading about plastics being detected virtually everywhere on Earth 色视频下载 from the bottom of the Mariana Trench to the Arctic Ocean; in rivers, lakes, and even in the air we breathe 色视频下载 I wanted to know how much was in Juneau.
色视频下载淚n the fall of 2019, I taught a new course on plastic pollution. I had twice as many students as expected. I decided to make use of the high number by sending everybody out to various environments in Juneau to collect samples.
色视频下载淲e collected water and sediment from various streams, lakes, and beaches; from the Mendenhall and Herbert glaciers, and we collected rainfall.
色视频下载淲e were amazed by how many small plastic fibers and fragments we easily found, especially considering we were seeing only a fraction of them using our fairly simplistic methods. In 2020-2021, I collected rain and snow samples with a couple of students, and added to the dataset I built with the class.色视频下载
What is a microplastic?
色视频下载淎 piece of plastic less than 5 millimeters in size, about the length of a grain of rice or smaller. So, you can see those that are at or close to 5 millimeters, but it色视频下载檚 very difficult to see much smaller than that without close inspection or a microscope.色视频下载
How does a Clorox bottle or a scrap of plastic wrap become a microplastic particle?
色视频下载淧lastic doesn色视频下载檛 really biodegrade, at least not on the scale of centuries or maybe even millennia. Instead it mechanically breaks apart into smaller and smaller pieces as it色视频下载檚 tossed around by waves, water, or wind, or driven over by vehicles. It can also become weakened and fragmented when baked in the sun.色视频下载
University of 色视频下载 Southeast graduate student Muriel Walatka gathers samples of beach sand to examine for microplastics at Auke Bay Recreation Area near Juneau in August 2019.
How did microplastics get everywhere on Earth, even 色视频下载?
色视频下载淢icroplastics are either intentionally manufactured so small, or come from larger plastics that break apart into smaller and smaller pieces over time. Humans are pretty much everywhere, and we bring plastics with us. Plastics are also dispersed via the atmosphere and ocean currents.
色视频下载淗ere in Juneau, microplastics get into the environment every time there色视频下载檚 a food wrapper left on the ground to be washed into a stream and into the channel, or a plastic bag picked up by the wind.
色视频下载淏ased on studies elsewhere, a major source is from the wear-down of car tires (which are partly composed of synthetic rubber) and brakes on cars. The laundering of synthetic fabrics is also a common source.色视频下载
Where did most of the Juneau microplastics come from?
色视频下载淚f local sources were important, then we色视频下载檇 expect to see more microplastics in the Mendenhall Valley, for example, where there are lots of roads, houses, and other human development and activities, but we didn色视频下载檛 find that.
色视频下载淕iven that many of the microplastics in the rain seem to be coming in from elsewhere, I can only suspect that most of it is coming from the Pacific Ocean, because this is the source of most of our wind and rain.
色视频下载淥ther researchers have looked into the mobilization of microplastics off the upper ocean, noting that they are generally low-density, lightweight, accumulate near the surface, and can be aerosolized easily by wind or wave action.色视频下载
The star marks Juneau's location in Southeast 色视频下载.
Despite Juneau色视频下载檚 extreme amounts of rain, ALL your samples had microplastics? Why wouldn色视频下载檛 they get washed out?
色视频下载淵es, they all had microplastics, and quite a few (an average of 57 fibers and fragments raining down on every square meter per day, about half of what has been measured in the Lower 48).
色视频下载淚色视频下载檇 collect the samples every one to three weeks, and so they were a composite over many rainy days. So, I don色视频下载檛 have the resolution over the course of a storm, but the samples indicate a large and steady source.色视频下载
Do microplastics harm animals? Human animals? Seems like we must ingest them all the time without noticing.
色视频下载淲hile larger plastics (fishing nets, six-pack rings, bottle caps) are well known to entangle and starve animals, the effects of microplastics are less well understood. There is some evidence of them being harmful, and they can be carriers of other contaminants.
色视频下载淲e most certainly ingest microplastics all the time. It色视频下载檚 in the soils, dust, plants, seafood, and even the salt we sprinkle on our foods. Plastic packaging breaks off onto our food, and plastic water bottles can shed particles into water. We might be eating a 色视频下载榗redit card色视频下载 per week [according to a study by researchers at the University of Newcastle in Australia].色视频下载
Are there microorganisms that eat microplastics?
色视频下载淵es, there have been some lab studies showing that there are some microbes and fungi that can break down microplastics, at least on a petri-dish/lab scale.
色视频下载淚t is really important that more research goes into producing sustainable substitutes for plastic and promoting less consumption, better waste management, recycling, and microbial breakdown of existing plastic.色视频下载
Since the late 1970s, the University of 色视频下载 Fairbanks' Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute. A version of this column was originally published in 2021.