Plastic concentrations found in freshwater environments are actually higher than those in so-called “garbage patches” in the ocean.
This is the conclusion of a study by the international Global Lake Ecological Observatory Network (GLEON), published in the journal ‘Nature’ by a team of 79 researchers.
About 14 million tons of plastic ends up in the ocean every year.but that’s not the only water source where plastic represents a significant intrusion.
“We found microplastics in all of the lakes that we sampled,” Ted Harris, a research associate professor at the Kansas Biological Survey & Center for Ecological Research at the University of Kansas, said in a statement. “Some of these lakes They look like clear, beautiful vacation spots to you. But we found those spots to be perfect examples of the relationship between plastics and humans.”
For his work, Harris teamed up with Rebecca Kessler, his former student and recent KU graduate, to analyze two Kansas lakes (Clinton and Perry) and Cross Reservoir at the KU field station.
“To do this we had to go out, put a net with little holes in it, drag it around for about two minutes, collect microplastic samples and send them (to the lead researchers),” Kessler explains.
The research project was designed and coordinated by the Inland Water Ecology and Management research group at the University of Milano-Bicocca (Italy), led by Barbara Leoni and Veronica Nava. The team sampled surface water from 38 lakes and reservoirs, distributed along gradients of geographic position and limnological attributes. It detected plastic waste in all the lakes and reservoirs studied.
“This work shows that the more humans, the more plastic,” Harris says. “Places like Clinton Lake have relatively low microplastics because, while there are lots of animals and trees, there aren’t many humans, compared to places like Lake Tahoe, where people live around it. Some of these lakes are seemingly pristine and beautiful, and yet that’s where the microplastics come from.”
Harris explains that many of the plastics come from something as seemingly innocuous as T-shirts. “The simple fact that people go swimming and wear clothes with microplastic fibers makes microplastics everywhere,” he adds.
The GLEON study cites two types of studied water masses that are especially vulnerable to plastic pollution: lakes and reservoirs in densely populated and urbanized areas, and those with elevated deposition zones, long water retention times, and high levels of anthropogenic influence.
“When we started the study, I didn’t know much about microplastics versus large plastics,” Harris recalls. “When this article says ‘concentrations as good as or worse than the garbage patch,’ you always think of the big bottles and so on, but You’re not thinking about all those smaller things.”
As he explains, “in Lake Tahoe there is not a large garbage patch, but it is one of the lakes most affected by microplastics. These are plastics that cannot be seen with the naked eye, but that, if observed with a microscope at 40,000 magnification, you see small jagged bits and other particles the size of algae or even smaller,” he says.
Part of Harris and Kessler’s enthusiasm for participating in this project was to highlight a region of the United States that is often overlooked.
“In this study, there’s a point in the middle of the country, and that’s our sample,” he says. “In Iowa, Missouri and Colorado there’s a huge swath of land with bodies of water, but often we don’t include them in those huge global studies. So it was really important to me to put Kansas on the map to see and contextualize what these differences are in our lakes.”
“The biggest takeaway from our study is that microplastics can be found in all lakes,” Kessler summarizes. “Obviously, there are different concentrations. But they are literally everywhere. And the biggest contributing factor to these microplastics is the interaction human with the lakes”.