Microplastics contaminate all lakes and freshwater environments around the world

New research has revealed that microplastics are pervasive in our lakes and freshwater environments, sometimes to an even higher degree than in the notorious oceanic “garbage patches.”

In an era when approximately 14 million tons of plastic waste find their way into our oceans annually, it’s easy to overlook the plastic problem lurking in our freshwater bodies. This disturbing international study, however, shows that our lakes, reservoirs and rivers are not immune to plastic pollution.

Ted Harris, associate research professor for the Kansas Biological Survey & Center for Ecological Research at the University of Kansas, and a participant in the study, commented on the surprising findings.

“We found microplastics in every lake we sampled. Some of these lakes you think of as clear, beautiful vacation spots. But we discovered such places to be perfect examples of the link between plastics and humans.”

Harris is a member of the international Global Lake Ecological Observatory Network (GLEON), a group of 79 researchers devoted to studying processes and phenomena occurring in freshwater environments.

How scientists studied microplastics in lakes

The team’s new paper, aptly titled “Plastic debris in lakes and reservoirs,” has been published in the renowned scientific journal Nature. It discloses that concentrations of plastic found in freshwater bodies can actually exceed those found in marine garbage patches.

For this research project, Harris collaborated with Rebecca Kessler. She is his former student and a recent graduate of KU. Together, they tested three water bodies in Kansas: Clinton Lake, Perry Lake, and the Cross Reservoir at the KU Field Station.

Kessler provided insight into their research methodology. She explained, “That entailed us going out, trawling a net with tiny little holes in it, dragging it for about two minutes, then collecting those samples of microplastics and sending them off to the lead researchers.”

The Inland Water Ecology and Management research group from the University of Milano-Bicocca in Italy orchestrated the study. Barbara Leoni and Veronica Nava spearheaded the study.

The Italian group sampled surface waters of 38 lakes and reservoirs. They focused on diverse geographical locations and limnological attributes and found plastic debris in every single one.

Freshwater microplastics directly linked to human activity

Harris points out that the study illustrates a clear correlation between human populations and the prevalence of plastics. Surprisingly, even seemingly pristine, scenic lakes can contain high levels of microplastics. This contamination often originates from unsuspected sources like clothing.

As Harris explained, “The simple act of people getting in swimming and having clothing that has microplastic fibers in it leads to microplastics getting everywhere.”

The study particularly highlights the vulnerability of two types of water bodies: those in densely populated and urbanized areas, and those with elevated deposition areas, long water retention times, and high levels of human influence.

Using the word “micro” doesn’t minimize the problem

Despite his knowledge of aquatic ecology, Harris admitted that this research was eye-opening for him.

“When we started the study, I didn’t know a lot about microplastics versus large plastics. When this paper says ‘concentrations as much or worse than the garbage patch,’ you always think of the big bottles and stuff, but you’re not thinking of all that smaller stuff.”

Participating in the study was not just an academic pursuit for Harris and Kessler. Their motivation stemmed from a desire to highlight a region of the U.S. that large global studies often overlook.

In Harris’ words, “In this study, there’s one dot in the middle of the country, and that’s our sample. So it was really important for me to put Kansas on the map to see and contextualize what these differences are in our lakes.”

Harris, who has been at KU since 2013, focuses his research on aquatic ecology, while Kessler graduated from KU in 2022 with a degree in ecology, evolutionary & organismal biology.

Their work confirms an unsettling fact. “The biggest takeaway from our study is that microplastics can be found in all lakes,” Kessler said.

“Obviously, there are different concentrations. But they are literally everywhere. And the biggest contributing factor to these microplastics is human interaction with the lakes.”

More about microplastics

Microplastics are tiny particles of plastic that measure less than 5mm in diameter, often too small to be seen by the naked eye.

They come from a variety of sources. These include larger plastic debris that breaks down into smaller and smaller pieces, as well as microbeads, a type of microplastic used in health and beauty products like exfoliants and toothpaste.

Microplastics also come from synthetic fibers shed by clothes, upholstery, and other textiles during washing. From there, they enter the environment via wastewater.

Causing substantial harm to our ecosystems

Microplastics have become a significant environmental issue due to their abundance, persistence, and potential to carry harmful substances. They are now ubiquitous in terrestrial and aquatic environments, from the deepest sea trenches to the highest mountains, and even in the air we breathe.

Once in the environment, microplastics can have a substantial impact on ecosystems. They can be mistaken for food by wildlife, leading to physical harm, such as blockages in the digestive tract, or starvation when animals consume too much plastic and too little food.

Plastics can also act as carriers for pollutants. These include heavy metals and persistent organic pollutants (POPs), which can bioaccumulate in organisms and potentially move up the food chain.

Research has shown that microplastics can be ingested by a wide range of species, from tiny zooplankton to birds, fish, and mammals. This has raised concerns about potential impacts on food chains and ecosystems, as well as on human health, although the exact risks are not yet fully understood.

New plastic detection methods for freshwater

The study of microplastics is a rapidly growing field. Researchers are developing new methods for detecting and quantifying these particles in the environment, studying their impacts on wildlife and ecosystems, and investigating ways to prevent their release into the environment.

Some governments and organizations have taken steps to address the problem. For instance, several countries have banned the use of microbeads in cosmetics and personal care products.

However, given the scale of plastic pollution and the wide variety of sources, tackling the issue of microplastics will require a multi-faceted approach. Some ideas include reducing overall plastic consumption and improving waste management practices.

Despite ongoing research, there’s still a lot we don’t know about microplastics, including their long-term effects on health and the environment. However, it is clear that they represent a significant pollution issue and that reducing our reliance on plastic and improving waste management practices are crucial steps in addressing this problem.