A floating “island” in the Pacific Ocean twice the size of Texas, the conglomerate of plastic trash known as the Great Pacific Garbage Patch bobs in the breeze, filled with straws that can lodge in the noses of turtles and six-pack rings and bottle caps that can strangle and choke sea creatures. It conjures a compelling visual—even if it falsely implies that the plastic-waste issue is contained, harming only the animals unlucky enough to brush up against the mass.
But what recent research suggests is that such easily visible garbage is “just the very tip of the iceberg” when it comes to the world’s plastic problem, says Matt Simon, science reporter at Wired and author of A Poison Like No Other: How Microplastics Corrupted Our Planet and Our Bodies. Beneath the surface, both literally and figuratively, is a massive number (in the trillions) of tiny microplastics and even tinier nanoplastics that are “accessible to the entire tree of life,” he says.
Occurring in a variety of shapes and colors, these mini plastics are unified by their size. Scientists refer to any plastics smaller than five millimeters (about the size of a sesame seed) as microplastics and have recently differentiated the very smallest of these pieces, smaller than 100 nanometers, as nanoplastics, which are not visible to the naked eye. The particular trouble that these tiny plastics pose is two-fold: It’s very tough to clean them up, and it’s very easy for them to pollute our ecosystems, as they can be ingested and inhaled by all living things.
As for where they originate? Like any large plastic object, called a macroplastic, microplastics can, in some instances, be manufactured intentionally. Think: glitter, foam balls for bean bags, and microbeads in exfoliating cleansers of the 2010s. (After those microbeads were deemed a hazardous pollutant in 2015, a U.S. law banned the production of rinse-off cosmetics containing them, foreshadowing the crisis to come.) Also in this category are what’s known as pre-production nurdles or pellets, plastics created in the size of rice grains that are then transported to manufacturers, where they’re melted down to create things like shampoo bottles and chip bags. And in transit alone, these pellets have been known to spill in mass quantities.
But where the real core of the microplastics issue lies is a far more familiar source: the macroplastics—plastic bottles, bags, containers, even synthetic clothing (which is a type of plastic)—we use on a daily basis. Though these products are often proclaimed to last forever, it’s more accurate to say that they degrade forever, breaking down into tinier and tinier pieces (aka microplastics, and eventually, nanoplastics) that pollute our environment, compromising the balance of our planet’s ecosystems and creating ripple effects for our own well-being. “I like to think of macroplastics as microplastic pollution just waiting to happen,” says Anja Brandon, PhD, associate director of U.S. plastic policy at Ocean Conservancy.
To that end, any single macroplastic can disintegrate into a theoretically infinite number of micro- and nanoplastics over the course of its endless existence—and starting right away, when it encounters water, heat, or physical friction. In fact, one of the biggest contributors to microplastic pollution is a process that includes all of the above: washing clothes in the washing machine, which sends millions of microfibers into water-treatment facilities, where they easily slip through filters and wind their way into waterways and the ocean.
The urgency of the microplastics crisis comes from its mega size: Humans around the globe currently produce roughly 300 million tons of plastic each year, more than ever in our history, and all of it will spend eternity breaking down, meaning the problem is a compounding one. As a result, microplastics are now everything, everywhere, all at once: Researchers have identified them not only in the ocean but in all compartments of the environment, from the air to freshwater systems and soil. “There’s nothing and nowhere on Earth that isn’t impacted by microplastics,” says Janice Brahney, PhD, associate professor at Utah State University’s Watershed Sciences department.
How the effects of microplastics on ecosystems pose a threat to global well-being
Microplastics in the ocean
Of all environmental spaces, the ocean is where scientists have conducted the most microplastics research, largely because they happened upon them there first, identifying “plastic particles” floating atop the Sargasso Sea in the Atlantic Ocean in the 1970s. It wasn’t until 1997 that Captain Charles Moore discovered plastics were accumulating in the ocean en masse—cue the plastic island—and 2004 that Richard Moore coined the term “microplastics” to refer to the tiniest offenders.
Further explorations revealed that clusters of plastic on the ocean’s surface are surrounded by far more debris than initially meets the eye. Rather than patches of macroplastics, these areas contain “a soupy mix of microplastics and nanoplastics accumulating in the water,” says Lea D’Auriol, founder of Oceanic Global, an international nonprofit dedicated to ocean preservation. This synthetic stew forms as the result of the sun breaking macroplastics into microplastics, which float alongside the 11 percent of plastics that enter the ocean already in micro form.
This plastic soup is then consumable by even the most miniature of ocean critters, which has implications for the entire food web that scientists have only begun to untangle over the course of the last decade. Research on ocean plastics prior to that had focused primarily on the consumption of macroplastics by larger ocean creatures, like whales and seabirds—because scientists knew that only these big animals could eat, say, a full plastic bottle or even a cap, says Dr. Brahney. In these studies, researchers found that the plastics could damage the digestive systems of these animals, leading to smaller meal sizes and even death.
Now, with the prevalence of microplastics and nanoplastics in the ocean, the issue of animals eating plastics extends to the smaller fish and microorganisms that can’t take down a full-sized macroplastic, says Dr. Brahney. And as nanoplastics and microplastics accumulate up the food chain—through even the tiniest zooplankton that accidentally eat them with algae, that are then eaten by larger fish that also eat nanoplastics and microplastics, and so on—they can cause direct harm at every stage. “These small plastics can lodge in the guts and gills [of fish], blocking their digestive tracts and leading them to feel full without absorbing key nutrients, and to stop eating,” says Dr. Brahney, “which can cause death.”
But these physical blockages aren’t the only threat to sea creatures; the breakdown of microplastics can cause chemical fallout, too. Manufacturers add a variety of chemicals to plastics—a set that includes upwards of 10,000 different options, some of them known toxins—to make them more malleable, flameproof, waterproof, durable, or any number of other qualities. And these aren’t chemically bound to the actual plastic molecules, “so they can leach out like water from a sponge as the plastic breaks down,” says Dr. Brandon. The composition of plastic also creates room for the microplastic molecules to pick up other chemicals in the environment, like heavy metals and pesticides, and even bacterial pathogens, and transport these toxic hitchhikers up the food web. This, again, threatens the continued availability of the fish that we eat and the gentle balance of the ecosystem of which they’re all a part.
Climate research also points to a few ways that microplastics can interfere with the ocean’s helpful ability to trap carbon in its depths; this process is essential for cooling our planet by drawing a huge amount of carbon dioxide out of the atmosphere. Usually, it works like this: Carbon dioxide dissolves into water at the ocean’s surface, at which point algae absorbs it, and then zooplankton eat algae, eventually releasing the carbon as part of their poop, which sinks down to the ocean floor (for good). But now, that zooplankton poop is laden with the tiny plastics that they’re eating, too, which is causing it to sink more slowly. At the same time, microplastics may be toxic to zooplankton, shortening their lives and thus reducing their overall ability to trap carbon—again, a process we rely on to draw carbon out of the air and keep the planet cool.
Microplastics in the air and atmosphere
Microplastics suspended in the air we breathe pose a relatively new threat to the health of the planet and its inhabitants. Only in the past five years have scientists begun to identify and quantify airborne microplastics, and it wasn’t until 2020 research by Dr. Brahney’s team that it became clear how extensively these little particles are circling the atmosphere.
“Ten years ago, I was like, ‘Microplastics are a marine problem, and I don’t work in the marine environment.’ But we’ve polluted the ocean for so long with plastic [and to such a large extent in recent years] that now, microplastics are being aerosolized off the surface of the ocean and are traveling back, through wind, into the terrestrial environment,” says Dr. Brahney. Not to mention the mass amounts of microplastics being whipped directly into the air by car tires wearing down on roads. Indeed, the concentration of suspended microplastics in the air is so large now (exact numbers are tough to come by, but thousands of tons is a ballpark estimate), they’re detectable even in regions of very high altitudes, hundreds of miles from urban centers.
Certainly, that means we’re breathing in microplastics. But from an ecological standpoint, the breakdown of plastics in the air also signals the release of potent greenhouse gasses like methane, says Simon. “It’s important to remember that 99 percent of plastics are still made out of fossil fuels—oil and gas,” he says, “and once they’re out in the environment and hit with sunlight, they release quantities of that carbon back into the atmosphere.” More carbon in the air just contributes, again, to rising temperatures by way of the greenhouse effect.
It’s important to remember that 99 percent of plastics are still made out of fossil fuels—oil and gas
Stocksy / Malin G
An atmospheric haze of microplastic and nanoplastic debris may also act as condensation nuclei, which are surfaces upon which water vapor can condense to form clouds. If this happens at high altitudes, the formation of “ice clouds” can trap the heat radiating off the Earth’s surface within the atmosphere, further contributing to global warming.
Microplastics in the soil
While microplastics can settle on soil from the air or get there through freshwater sources—many of which are as heavily polluted with plastics as the ocean—they can also make their way into soil through the common process of using “biosolids” (aka solids filtered out of water in wastewater treatment facilities) as agricultural fertilizer, says Dr. Brandon.
Typically, when we wash our hands, shower, cook, use the toilet, or do laundry, the resulting wastewater flows to a treatment plant, where solids (like dirt, debris, and food particles) are cleared from the liquid. This process captures much of the microplastics (as discussed, some microplastics do slip through filters and run into our waterways), which amass in the resulting biosolids. Because those biosolids are nutrient-dense (think of all the organic matter they contain), they’re often applied to farmland as fertilizer. Unfortunately, this sends all their constituent microplastics onto the soil, where they become, again, an environmental pollutant.
The ripple effects for the soil ecosystem may be as significant as they are for marine life. For starters, microplastics can change the balance of the local microbiota, or the community of microbes responsible for recycling nutrients in the soil, says Dr. Brahney. When plants die, these microorganisms get to work, breaking down their organic material into bioavailable nutrients that allow for new plant growth. “Without this nutrient-recycling process, we see reduced plant height and less new growth,” says Dr. Brahney, “which has implications for food security.”
To similar effect, microplastics “have also been shown to get into the bodies of critters like earthworms—which we rely on to process soil and create fertilizer for crops—and to reduce their reproduction or shorten their lifespans,” says Simon. Paired with physical changes to the soil prompted by microplastics, including a reduced capacity to hold water, these harms to the soil ecosystem may reduce crop yields, again threatening our own livelihoods.
How the microplastics that we’re consuming and inhaling may affect our health directly
While the ripple effects of microplastics on the planet’s ecosystems will certainly jeopardize our long-term well-being, the question of how microplastics affect our health imminently—as in, right now, as you inhale microplastics, or when you consume microplastics in food—is less clear.
After all, it’s tough to study. You can’t exactly ask people to eat or breathe in microplastics, and see what happens. And even epidemiological studies, where scientists might analyze the level of microplastic buildup in people with certain illnesses, are tough to organize. “You don’t have a control group to compare against that hasn’t been widely exposed,” says Dr. Brandon.
But the fact that microplastics are indeed so prevalent is reason for concern, in and of itself, especially given that several studies have pointed to levels of microplastic exposure being higher inside our homes than outside (not shocking, given we’re surrounded by plastics at home, and ventilation is worse in enclosed environments). Exploring how these microplastics amass in our bodies, recent studies have found them “everywhere scientists have looked,” says Dr. Brandon. So far, that’s in lung tissue, poop, placentas, breastmilk, and even blood.
Separately, scientists who have assessed the potential impact of microplastics on human cells using tissue cultures in a lab have found that they can induce cell damage and even death. And similar research using models of the human epithelial lung and gut barriers (aka the tissue that lines the lungs and gut) has shown that microplastics can create small openings in those barriers and slip through, potentially triggering an inflammatory immune-system response.
To Cezmi Akdis, MD, PhD, director of the Swiss Institute of Allergy and Asthma Research, it’s this potential for microplastics to break down epithelial barriers that’s most concerning. “The open spaces in the epithelial barrier can allow bad bacteria to translocate, moving in between cells, and as the immune system tries to expel the microplastics and the bacteria, it cannot differentiate between good and bad,” he says. This can disrupt the overall bacterial balance and trigger inflammation, both of which are at the root of a wide variety of chronic diseases.
At the same time, microplastics tote along with them all their chemical additives when they enter the body, including endocrine disruptors like bisphenols and phthalates—which may pose a particular threat to infants and toddlers, says Simon. “If you are in these really delicate developmental stages as children, you do not want the endocrine system disrupted,” he says, referencing the key role of hormones in healthy growth and development. And that’s especially worrisome given that babies are also known to have high exposure to microplastics, by virtue of consuming warm formula or breastmilk in plastic bottles, putting plastic toys in their mouths, and crawling around on the floor, where microplastics are known to settle.
Coupled with the trickle-down effects of microplastics on ecosystems noted above, these initial harbingers of harm in people are reason for collective action to turn off the plastic tap. Buying, using, and tossing less plastic—and opting for reusable materials, like glass or aluminum, or biodegradable ones, like paper—is one way we can all help slow the flow. As is reusing and properly recycling as much as possible in order to move toward a circular economy, where we’re sending fewer materials, overall, into the environment as trash. But ultimately, legislation is necessary to prompt manufacturers to switch away from plastics—and that’s now in the works.
California recently passed SB54, a law that requires 100 percent of the packaging in the state to be recyclable or compostable by 2023. And four states (California, Colorado, Maine, and Oregon) have passed extended producer responsibility laws, which put the onus on manufacturers to consider end-of-life solutions for any product. More broadly, the federal Break Free From Plastic Pollution Act, designed to reduce the production of single-use plastic across the U.S., is gaining cosponsors, and there’s a United Nations treaty under negotiations right now that aims to put an international cap on plastics production.
Though our microplastics problem is the fallout of a macroplastics crisis we let go on for too long, the experts are still optimistic about our ability to turn the tides. After all, plastic is a relatively new staple in our arsenal of materials. “One statistic I always come back to is the fact that half of all of the plastics we have ever made have been made in the last 20 years,” says Dr. Brandon. “That means, what we do in the next 20 years matters a whole heck of a lot.”