What is microplastic anyway? Inside the insidious pollution that is absolutely everywhere

Microplastics are linked to infertility, cancer, immune diseases and other serious health problems

By Matthew Rozsa

Staff Writer

Published July 17, 2021 10:00AM (EDT)

Microplastic in spoon (Getty Images/Olena Sakhnenko)
Microplastic in spoon (Getty Images/Olena Sakhnenko)

A 2020 study found that there may be more microplastics in some waters than zooplankton, a group of plankton that include tiny animals and some immature larger animals. That may not seem like a big deal, but countless aquatic species rely on zooplankton as a food source; their experience is tantamount to accidentally eating a credit card half the time you try to eat what's on your plate.

Indeed, plastic pollution is one of the biggest ongoing threats to the planet, easily on par with climate change and the loss of biodiversity. Plastics are responsible for poisoning our bodies, reducing our fertility rates and destroying wildlife both on the land and in the sea.

Yet plastics pollution doesn't mean floating bottles and utensils, medical equipment and random consumer junk. Plastic pollution from these and other goods are broken down in the ocean into tinier and tinier pieces. Much plastic pollution is so tiny that they appear as grains, or perhaps are invisible to the naked eye. These are known as microplastics; and while they are tiny compared to the vast belching smoke stacks and mushroom clouds we associate with the most ominous symbols of pollution, microplastics are no less ominous.

What are microplastics?

"A microplastic most typically is defined as a particle that is five millimeters or less across or in length," Rolf Halden, Director of the Biodesign Center for Environmental Health Engineering at Arizona State University, told Salon. "Even there people disagree, but let's say it's just a diameter of five millimeters or less that makes for a microplastic." Halden says that they are "plastic shavings or debris," which floats in the ocean and created by continually being ground down by the surf. Some microplastics are also remnants of rubber tire shavings that blow off of highways as cars travel — these are rubber polymers. 

Jacqueline Doremus, an Assistant Professor of Economics at Cal Poly who, among other things, is an expert in evaluating environmental policy effectiveness, explained that the plastic industry itself is connected to the petrochemical manufacturing industry, which plays a big role in pollution. This economic angle explains how plastics have become so pervasive and, as a result, microplastic pollution has become such a major environmental problem.

"Plastic is a byproduct of petrochemical manufacturers," Doremus told Salon by email. "Decreases in demand for oil and gas mean producers betting on plastic. At the same time, more than three-quarters of plastic additives are not disclosed to researchers, the public, or regulators because they are protected as intellectual property or are improperly documented. So we have two forces at work: strong incentives for a powerful industry to increase plastic production and a poor understanding of the sometimes toxic additives they use."

Where are microplastics?

There is no easy way to answer this question: They are literally everywhere. You cannot escape them.

"Microplastics are insidious and now cover large areas of our planet," Mary Crowley, Founder and President of Ocean Voyages Institute, wrote to Salon. "Besides being found in the deepest part of our ocean, the Mariana Trench, microplastics are also found atop the Rocky Mountains, the Pyrenees Mountains, the Arctic, the Antarctic and throughout the world's oceans and deserts — everywhere!" Even worse, because plastic is not biodegradable (that is, able to decompose because bacteria or other organisms consume it), it is going to stick around for centuries.

"Microplastics end up being ingested by small organisms which are in turn ingested by larger organisms such as fish and birds and via this route, plastic enters into our planet's food web making its way up the food chain," Crowley explained. "Microplastics and larger pieces of plastic are now commonly found filling the stomachs of fish, birds, whales, dolphins, seals and turtles, causing illness and mortality."

Why are microplastics dangerous?

Crowley also elaborated on the ways that microplastics endanger human health.

"Microplastics contain toxic chemicals and hormone altering compounds, which can affect human health in areas ranging from reproduction to immune function," Crowley told Salon. "More studies need to be done for us to begin to gain a full understanding of all the effects microplastics have on human health and the health of our oceans, but from what we can observe, we know plastics are made with substances that are not meant to be ingested. On a macro level, microplastics tamper with the ocean's ability to sequester carbon through plankton, affecting the very air we breathe."

Halden said that laypeople may wonder why we make so many products out of plastic if it is toxic or hazardous to human health.

"The answer to that is that, historically, we have made choices to enough of the ingredients to make plastics that in hindsight turned out to be very poor ones," Halden explained. One example is vinyl chloride, which scientists later learned is a potent carcinogen. Obviously all we have to do is keep it out of products that could contaminate our food and we should be fine, right?

"If you look to food, we don't use PVC [polyvinyl chloride, a polymer of vinyl chloride] to package food," Halden said. "We use a polyethylene and other polymers, right? And they are initially safe for the purpose they're intended for. However, since we make so much of it and it gets out into the environment, then it grinds down. They are changing their chemical makeup and their physical appearance and they become a health hazard."

To illustrate the processes at work here, Halden suggested that people imagine a disposable plastic yogurt cup. Once they eat the yogurt, they throw away the cup. What happens to it? The chances are pretty good that, eventually, it will find its way into a body of water like the ocean or a river.

"It floats there for a long period of time and can absorb a lot of air and water pollutants," Halden explained. "It becomes like a toxic float and its surface characteristics can change so it almost looks like a piece of asbestos. And we know that foreign particles that get into our lungs or other organs can cause inflammation and cancer. So the material changes over time and with it the risk, and that is something that is not intuitively understandable by a lay person when they evaluate plastics and wonder, 'Should I buy more plastics? Am I doing the right thing here? Or should I change my, my behavior?'"

How can we protect ourselves from microplastics?

Lisa Erdle is the Manager of Science & Innovation at 5 Gyres, a nonprofit devoted to fighting plastic pollution.

"Once microplastics are in the environment, they are nearly impossible to clean up," Erdle wrote to Salon. "There have been some technologies designed to 'clean up' the ocean, for example, but these are expensive, have other negative impacts on the environment, and are exceedingly difficult to implement at scale. However, other technologies, like those that capture microplastics closer to the source, are effective at capturing microplastics before they enter the environment." One example of this are washing machine filters that capture microfibers before they can infiltrate aquatic environments; another are storm drain traps that capture plastics on our roads before they enter bodies of water.

"Since there are many different sources of microplastics to the environment, it is likely we will need a range of different solutions to prevent their emissions to the environment," Erdle observed.

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Doremus framed the question as being one of protecting our basic freedoms and argued that manufacturers themselves need to be held accountable.

"The problem boils down to rights," Doremus wrote. "Who has the right – companies to produce plastic without consequences? Or people to have a threshold of plastic they can expect in the air we breathe and the water we drink?"

From this vantage point, Doremus urged a number of approaches including taxing plastic, reclassifying it as a pollutant so it can be regulated and force companies to "take back" their plastics. On an individual level, people can change their lifestyle to reduce their plastic output.

"Wash your clothes less and line dry, this avoids microfiber pollution and carbon emissions – win-win," Doremus argued. "Same with carpooling and reducing driving, which reduces tire fibers, carbon emissions, and local pollutants that increase asthma.If you smoke cigarettes, be careful to dispose of the butts in the trash, as they contain highly toxic microfibers. Avoid plastic bottled beverages, as the manufacturing process likely introduces microplastic. Reduce your use of plastic where you can."

She added, "Start small and be kind to yourself if you can't avoid it. It's not you – it's us."

By Matthew Rozsa

Matthew Rozsa is a staff writer at Salon. He received a Master's Degree in History from Rutgers-Newark in 2012 and was awarded a science journalism fellowship from the Metcalf Institute in 2022.

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Environmentalism Explainer Microplastics Plastic Pollution