Amid increasingly dire reports on climate change and political upheaval, this year a new menace came to dominate the news cycle: microplastic pollution. Scientists revealed that it’s blowing in the air and swirling in the seas and tainting our food and water, with as yet unknown effects on human health.
Microplastic pollution isn’t particularly new to science—researchers have been monitoring the problem for decades. But new technologies and techniques are making it easier to test environments for tiny pieces of plastic, say Deonie Allen and Steve Allen, environmental scientists (and spouses) studying such pollution at the University of Strathclyde in Glasgow, Scotland. Thanks to these new tools, it’s now apparent that microplastics are absolutely everywhere.
“I think part of the reason why this year’s been so big is because people are pushing the boundaries of the way that we do analysis,” says Deonie Allen. “So we’ve advanced the way that microplastics are identified and quantified.” It used to be that researchers would poke through a sample of particles with a hot needle, seeing what would deform under the heat to distinguish organic bits from plastic bits. But now plastics researchers are adapting microscopy techniques from other fields—for instance, using lasers to count particles like microbiologists count bacteria.
There’s also been a mass migration of scientists from other fields into microplastic research in recent years, says Scripps Institution of Oceanography oceanographer Jennifer Brandon, because microplastic pollution is tainting virtually every corner of Earth. She has a friend who researches bird parasites, for example, but is now helping expose the plastic menace. “The more and more birds she cut open, the more and more plastic she found, especially in the sick birds that were then more likely to develop a parasite,” Brandon adds. “And so then she became a plastic scientist by default.”
In part it’s fueled by an informational feedback loop: In the past few years, studies have been trickling out showing that microplastic is everywhere, which gets media attention, which gets the public’s attention, which gets governments’ attention, which frees up more money for more studies. “For a long, long time,” says Brandon, “people have been asking me: Am I eating microplastic? Is it in my food? And this was one of the years where we could definitively say yes, unfortunately you are.”
The core problem with plastic is that it’s highly durable, and when it does break down, it just breaks into ever smaller pieces that persist in an ecosystem. The smaller researchers can go, the better they understand how the size might affect the way a microplastic distributes itself in a given environment. A particularly troubling revelation: baby fish are mistaking microplastic for prey, according to findings published last month. What’s not known is how the size of the particle affects the health of the fish. Big ones might clog their digestive systems, while very small ones might pass through gut tissues and into organs.
Likewise, the size of microplastics raises big questions for human health as well. Most of the particles we eat and drink pass through our bodies, research shows. But it’s not clear yet whether really tiny particles might be working their way through the walls of our guts, or passing through the blood-brain barrier, a sort of protective border that keeps toxins in our blood from reaching the brain. “It’s becoming more obvious that we really need to be looking in the nano realm, because that’s where it becomes more dangerous,” Steve Allen says.
Size also influences how microplastics circulate. You’d assume a plastic fiber would blow around more readily than a chunkier fragment, but there just isn’t much data to prove it. And might different types of plastic, like polystyrene and polyethylene, swirl in water and blow in the winds differently? Thanks to better technology for collecting and testing samples, researchers are hoping to soon find the answers to these questions.