The Tiniest Terror: The unknown threats behind microplastics, and how researchers are trying to stop them

Plastic pollution on a beach

By Karyn Simpson
Medill Reports

Two summers ago, Lisa Erdle cast a net from a research vessel on Lake Ontario, dissected the unlucky fish in the boat’s laboratory, and placed each of their guts carefully in jars to be frozen and sent back to her lab in Toronto.

“You need a little bit of a strong stomach,” Erdle said of the gory work, but these macabre parcels weren’t the most disturbing product of that trip. It’s what can’t be seen at first glance that is most alarming.

Back at her lab, University of Toronto Ph.D. candidate Erdle puts her carefully stored fish guts through a chemical digestion process that eats away all the organic matter. It’s then that, through the microscope, she can start to see the tell-tale multicolored signs.


Or, more accurately, microplastic – miniscule bits of plastic that are most effectively described using words like “teeny” and “itsy” but are poised to be the world’s next big regret.

Why? Because microplastics are everywhere, likely including inside your body by way of Chicago tap water, Great Lakes beer, and internationally sourced salt, according to a study by University of Minnesota School of Public Health Ph.D. candidate Mary Kosuth. And because we don’t know how consuming them will affect us.

“We don’t have all the answers for what it does to us when it gets into our bodies, but I think it’s safe to say that most people don’t want to have microplastics in their beer, in their water and in their fish,” Erdle said. “We’re literally eating our trash.”

We also don’t know where they come from, specifically. Generally, they come from everywhere – from pieces of trash and plastic that degrade over time in the Great Lakes, or from your clothes, towels, bedsheets and pillows in the form of microfibers, a subset of microplastic.

Have you ever seen dust floating in the air in front of your window on a sunny day? Those are most likely microfibers, Erdle and Kosuth both said – it’s an effective example of something that, at less than 5 millimeters long, you typically need a microscope to see. These synthetic fibers can drift from your clothing and other cloth items though normal use, but they shed en masse every time such articles are washed.

“Whether it’s, you know, a fleece or anything that has elastic in it, every time you wash those pieces of clothing, teeny little microscopic fibers that are made out of plastic are washing down through your washing machine and out through sewage treatment plants into rivers or the Great Lakes,” said Jennifer Caddick, vice president of communications and engagement at the Alliance for the Great Lakes. “And figuring out how to tackle those kinds of issues, I think, is going to be a lot more complex. I don’t know of any easy solutions.”

A single load of laundry might release upward of 100,000 microfibers, Erdle said. In collaboration with other scientists at the University of Toronto’s Rochman Lab, Erdle released a study in January that compared the effects of different after-market filters that can be put on washing machines to catch microfibers – similar to the way lint filters on dryers work.

By washing polyester fleece blankets from Ikea both in a traditional washing machine and in machines equipped with different types of filters, Erdle and her team determined that adding a specific filter (known as a Lint LUV-R) to a washing machine could reduce the number of microfibers being released into wastewater by an average of 87 percent, according to the study, which is titled “Capturing microfibers – marketed technologies reduce microfiber emissions from washing machines.”

Unfortunately, without these filters, the 100,000 tiny plastic filaments shed from your clothes are taken with the dirty washwater to the nearest wastewater treatment plant. They’re filtered out here into “sludge,” Erdle said, which is the semi-solid, generally organic waste left at the end of the treatment process. This sludge is, in many cases, sanitized and used as fertilizer for local farming operations.

“So many of those microfibers probably are captured at the wastewater treatment plant level, but they can still enter the environment,” Erdle said. “If that sludge is used as a fertilizer, through rain and erosion, those microplastics that are applied onto fields can make their way back into water systems.”

In fact, Erdle said in her study that more than 96 percent of microfibers can be removed from effluent in the wastewater treatment process, citing a 2005 study by Steve A. Carr, Jin Liu, and Arnold G. Tesoro titled “Transport and fate of microplastic particles in wastewater treatment plants.” While this sounds like a laudable track record, Erdle said that treatment plants often have programs that allow sanitized “sludge” to be given or sold to local farms for use as fertilizer or topsoil. When it rains, soil erosion and runoff can take those microscopic fibers that once belonged on your favorite sweater and wash them back into rivers or, ultimately, the Great Lakes, where they end up in the belly of some unsuspecting fish in Erdle’s laboratory.

The Metropolitan Water Reclamation District of Cook County has a similar program in place for its sludge. On its website, the district advertises a product called “EQ Biosolids,” which they describe as a “product of wastewater treatment” that is used as fertilizer for farmland in several neighboring counties and as compost in Chicago. EQ is industry-speak for “exceptional quality,” and the district’s biosolids appear to meet or exceed all the legal health requirements for such fertilizer, according to the data on its website.

The problem? Microfibers are not included in these regulations. This means treatment plants aren’t looking for them when they test biosolids for other contaminants. And this means that these plastic fibers can end up in the fertilizer made from biosolids, which is then spread across farms and fields.

“Our wastewater treatment plants are really a modern marvel. They’ve done so much to increase the quality of health of our environment,” said Timothy Hoellein, Ph.D., associate professor at Loyola University and head of the Hoellein Aquatic Ecology Lab. “But this issue of small plastic particles in the water and in the wastewater is not something that is part of our regulatory framework, so the wastewater treatment plants weren’t designed to treat this material. And there’s no legal obligation for them to do so either.”

Researchers and engineers at Chicago’s treatment plants want to help improve the water environment, said Guanglong Tian, Ph.D., an environmental scientist at Chicago’s Stickney Water Reclamation Plant. Stickney is the world’s largest water treatment plant, and the campus’ low brick buildings, treatment ponds, and biosolids-testing greenhouse sprawl across the land directly adjacent to a rather sleepy neighborhood in suburban Cicero, Ill.

These researchers and engineers want to help, but because microplastics aren’t regulated by the federal Environmental Protection Agency (EPA), the treatment center doesn’t have the technology or methods necessary to test for or filter them out, Tian said.

“The main concern for us is pathogens and metals,” Tian said, “and of course the trace organics.”

The process of getting microplastics covered under federal regulations, the same way that heavy metals and other pollutants in wastewater are regulated, is twofold. Scientists would have to develop tests to accurately measure microplastics on the mass scale required for treatment plants, said John Chavich, assistant director of monitoring and research at Stickney Water Reclamation Plant. But first they would have to prove that these microplastics are worthy of concern – something Erdle hopes to accomplish with her research.

“One of the first steps is you’d have to determine what kind of levels are toxic to the environment,” Chavich said. “So we would need to know that, and then the EPA could set up a limit for permits, and they’d also select and approve methods that they want labs like us to use to measure it.”

No testing has yet been done to see if microfibers remain in biosolids from the Stickney plant or any other Metropolitan Water Reclamation District treatment plant, so we don’t fully know if these bits of plastic are at risk for being washed into Lake Michigan when used as fertilizer or field toppers. The district does have regulations prohibiting these fertilizers from being used close to a waterway, Tian said. The safety data sheet for the district’s biosolids recommends users “do not let product or runoff from product enter drains or water bodies,” and users are required to sign a contact stating that they will not employ biosolids within 10 meters (about 33 feet) of a waterway, Tian said.

Even if microfibers are in the biosolids, and even if the runoff were to surpass the required 10-meter buffer zone, these fibers may still not be making their way into Lake Michigan, Metropolitan Water Reclamation District Commissioner Debra Shore said.

“Much of the storm water runoff in Cook County ends up in the water ways that flow away from the lake and not into the lake,” Shore said, meaning that runoff from biosolids may not contribute to microfiber pollution in Lake Michigan.

Likewise, the treated wastewater from the Metropolitan Water Reclamation District plants is discharged into waterways like the Des Plaines, the Illinois and the Mississippi, which flow away from Lake Michigan.

But even if this runoff isn’t directed into Lake Michigan, any microfibers that might be present may still pose a risk for the freshwater ecosystems and fish they do encounter. But why should the average person-who-is-not-a-fish care about microplastic and microfibers turning up in biosolids runoff and in Great Lakes trout, beer, and tap water?

The biggest concern might be the possibility that the microplastic, once in our digestive system, may leach harmful chemicals into our bodies.

“The plastics themselves have additives that could leak from the plastic into the organism that ingests it,” said Mary Kosuth, author of the research article, “Anthropogenic contamination of tap water, beer, and sea salt.” “There’s been some debate about whether or not it’s a problem because we don’t eat the entire fish, you know. We just eat the meat of the fish – we’re not eating the digestive tract, then perhaps the exposure’s very low. That’s not the case with something like shellfish, however, where we’re eating the entire organism. It kind of depends on what you’re ingesting.”

It’s not just fish, though. Kosuth’s study showed that the average adult might consume up to 5,800 microplastic particles a year from only three sources: tap water, Great Lakes beer, and internationally-sourced salt.

Eighty-eight percent of this comes from tap water, according to Kosuth’s study, which analyzed 159 samples of tap water from 14 countries.

Three of these samples came from Chicago tap water. While the study didn’t release the city-specific data, it did report that an average of 9.34 particles were found in each liter of water sampled from the U.S.

Kosuth also sampled twelve brands of beer that was made with water from the Great Lakes. Four of those drew water from Lake Michigan. Particles were found in each sample of beer, meaning that microfibers made it all the way through the beer-making process without being filtered out – a certain hazard when dealing with plastic particles this size.

While the numbers of particles found in the beer and water were small – all clumped together, they still probably wouldn’t look like much, Kosuth said, or even really be visible to human eyes – we don’t know at what concentration the plastic could begin harming people.

Researchers know that plastics adsorb chemicals from the environment around them, Kosuth said in her study, meaning while these microplastics and fibers are in the water, they could be taking a sampling of the other chemicals also in the Great Lakes. More than that, though, these chemicals can “desorb” from the plastic after they’re ingested, Kosuth wrote, meaning the chemicals can leave the plastic and enter the gut of whatever fish or human ingested them.

There’s also a risk that these toxins might grow more concentrated as they move through the food chain, as a fish is eaten by a bigger fish is eaten by a human, for example.

“We know that plastic is starting to sort of accumulate up through the food chain,” Caddick said. “But we also know that those tiny pieces of plastic can sort of accumulate toxins, so toxins in the water can get attached to plastic. So there are concerns about whether or not any toxins can sort of accumulate through the food chain as well.”

While some scientists are worried about these possible effects, there hasn’t been any conclusive research saying that consuming these nearly invisible bits of plastic is harmful. But on the other hand, there also hasn’t been conclusive research proving that doing so is harmless.

“We want to make sure that we’re not being alarmist about this,” Hoellein said. “I understand that a lot of people, when they hear about the possibility, are worried, and they’re worried about not only the fish, but their own health if they’re eating the fish. That is a justifiable concern, and I don’t want anyone to feel like they have to jump to conclusions or panic or anything. We’re wondering the same questions, and we’ll try to figure out the answer.”

There has been substantial research on the effects of plastic consumption in ocean fish, Hoellein said, but the same research in freshwater fish is lagging behind. While it’s true that there may be no effect, Hoellein said there may be subtle consequences from plastic ingestion that could pose a threat – a possibility that Erdle is exploring in her research with hopes that conclusive results could lead to future regulations.

Most of the microplastic Erdle finds in her fishes’ stomachs are microfibers.

While there isn’t much current research on the effects of consuming microfibers specifically, which also made up 98.3 percent of the plastic collected in Kosuth’s 2018 study, Erdle said that studies about the effects of microplastic in fish can be extrapolated to predict some of the dangers of microfiber ingestion.

For example, as with general microplastics, these effects can be either physical or chemical, Erdle said. For fish, she explained, eating microplastics may cause abrasions on the inside of fishes’ digestive tracts, cause blockages in their intestines, or cause them to suffer from malnutrition because they are eating plastic – with no nutrients or calories – instead of food. The human equivalent might be munching on cardboard.

It’s the chemical effects, though, that may have a greater risk of relatability to people. And it’s in these effects, Erdle cautioned, that microfibers might harbor unique threats.

For example, microfibers have ingredients inside the fibers themselves, Erdle said. This could include fabric dyes or additives that make textiles soft, water-resistant, or fire-retardant – which are made of chemicals that could be harmful if released inside your body. Textiles, which shed microfibers, also pick up contaminants from the air around them.

“That sweater that you’re wearing, it can do that,” Erdle said. “It can pick up chemicals from the environment and act as sort of a passive sampler, and it also might have chemicals that were just in it when it was made…So there’s a lot of chemicals in the manufacturing process and then also chemicals that can interact with the textiles or an item when you’re just in the world in polluted places.”

To get concrete evidence about the potential effects of consuming microfibers on both humans and fish, Erdle is deep-diving into her research – fish guts, multi-colored plastic and all.

Erdle’s research is split into two sections: the first, where she studies the stomach contents of wild-caught Rainbow and Lake Trout from Lake Ontario and Lake Huron, confirms that there are microplastics and microfibers in the lake and that the fish are eating them. The second section is meant to begin to address the question of what happens when organisms consume microfibers.

To do this, Erdle has set up a controlled, in-lab experiment using only lab-reared fish – fish that were born and raised in the lab and therefore have not been exposed to the myriad unknown pollutants that wild-caught fish encounter in the Great Lakes. She feeds some of the test fish regular fish food, while she feeds another group fish food laced with microplastics. The goal is to study the fishes’ reactions when exposed to plastics for different time periods and at different life stages to help uncover any potential dangers of microfiber and microplastic consumption.

“We’re doing it all with the same concentrations that fish might be exposed to in the wild in a very controlled way to see what some of the effects will be,” Erdle said. “Because when we catch fish from the wild, even if they have lacerations in their stomach or they have chemicals in their blood, we don’t know whether or not those came from plastics or from other things they may be exposed to in the Great Lakes.”

While trying to figure out how these plastic particles might affect us seems paramount, there’s also the environmental impacts to consider. Regardless of intention, we’re peppering the Great Lakes with microfibers and microplastics, and the fish are taking it for food.

The Alliance for the Great Lakes partnered with the Shedd Aquarium to do several educational trips onto Lake Michigan last summer, Caddick said. On these trips, they compared real-time water samples from the lake to known “clean” water samples. What was most surprising, Caddick said, was that the phytoplankton and algae – a mealtime favorite for fish in Lake Michigan – from the clean sample looked almost identical to the microplastic in the sample from the lake.

“Animals mistake those tiny plastic pieces for food,” Caddick said. “They think, ‘Oh hey, here’s another bit of algae or phytoplankton that I’m supposed to be eating.’”

Erdle had a similar experience when she worked on a sailboat on the Great Lakes teaching students about water ecology.

“We looked at zooplankton and phytoplankton, and mixed in with the plankton there were these tiny microplastic particles,” Erdle said. “It really surprised me that there were small pieces of plastic sort of mixed in with all of the phytoplankton and zooplankton.”

Shortly thereafter, she decided to study the topic in depth for her Ph.D. The hope, Erdle said, is that her research will provide the verifiable information about effects of microplastics and microfibers necessary to influence policy changes that would reduce microplastic pollution.

“We hope that some of this research can help inform policies,” Erdle said, “because we know that microfibers are really common in the environment, but we don’t have many studies that point to what the specific effects could be. And once we have that information, we can hopefully draft policy.”

She wants to see the filters, which were proven successful in her last paper and are now being tested on the community level in Perry Sound, make their way to pre-market manufacturing, meaning they would come installed in washing machines the same way lint filters come installed in dryers.

She hopes to complete her current project (yes, the one with the fish guts) sometime next year.

While policy change isn’t as simple as just installing filters, Erdle seems on the right track. Microplastic pollution in the Great Lakes is as varied as its multitude of sources, and Erdle, Hoellein and Tian all agree that the most immediate solution is to control the original source.

“In many cases, the wastewater treatment plant operators would say to us, ‘If people don’t want this material to come to the wastewater treatment plant, they shouldn’t flush it down the drain,’” Hoellein said. “And it makes a lot of sense. They’re generally saying that the real solution is prevention; it’s not a clean-up.”

Prevention isn’t simple, though. Chicago alone releases an estimated 2,850 metric tons – just over 6 million pounds – of plastic into the Great Lakes every year, according to a study by Matthew J. Hoffman and Eric Hittinger titled “Inventory and transport of plastic debris in the Laurentian Great Lakes.” This plastic, which could look like anything from the water bottle that blew away from your picnic table to a shred of a plastic grocery bag, slowly breaks down in the Great Lakes, becoming – you guessed it – microplastic.

Movements to regulate this kind of plastic – and, subsequently, microplastic – pollution have popped up across the country in the form of bans on plastic drinking straws and plastic bags. These sorts of bans might be a gesture in the right direction, but they aren’t the end-all-be-all for curbing microplastic pollution, and policy-makers need to weigh the positive and negative effects of these regulations, Caddick said.

“It’s so important, as we think about these policy solutions, to really think carefully and include a lot of different people in the conversation,” Caddick said.

Banning straws likely isn’t going to make the biggest impact on plastic pollution, Caddick said, and doing so would make life significantly harder for people with certain disabilities.

“In the disability community, there’s a lot of folks who depend on single-use plastic straws in order to be able to drink – sometimes it’s to drink in a dignified way, but sometimes it’s to drink at all, to take any kinds of fluids that’s needed,” said Adam Ballard, advocacy manager for Access Living, a disability advocacy group.

Some people with disabilities have a strong bite reflex, Ballard said, or produce a lot of saliva, meaning that metal or paper straw alternatives can be ineffective or even dangerous, and banning plastic straws could mean that some people in this community would no longer be able to drink outside of their homes.

“We know that straw bans, for instance, really aren’t going to have the biggest – kind of, bang for the buck, as far as keeping plastic pollution out of the Great Lakes,” Caddick said. “But straws are also really important to many people with disabilities.”

Focusing on banning or decreasing use of other single-use plastics could be less damaging to members of our community, while also making a bigger impact.

“Even other single-use plastic items like packaging,” Ballard said. “If we can go after that, we’ll make a bigger impact, too. It’s not just about making accommodations for our community, it’s also about having a bigger impact if we go after other sources first…The message is please, please listen closely to what we’re saying and believe us. A lot of us, most of us, we care about the issue, but we also care about being able to drink. Take the time to listen to us.”

Major policy reform – the kind that would help Erdle see less microplastic in the guts of the fish under her microscope – will take time. It will follow the science, which is still in the process of trying to answer the questions of how this affects us and the Great Lakes’ ecosystems. One thing, though, is certain: Any future policies that aim to curb plastic and microplastic pollution should be informed by the science – what will make the biggest impact – as well as the needs of our community.

Photo at top: Plastic pollution is prevalent on the beaches of the Great Lakes and oceans alike. (Photo Credit: Pixabay)