Approximately 14 million tons of plastic reach the ocean annually. However, that is not the sole water source from where plastic denotes a considerable intrusion.
Image Credit: The University of Kansas
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.
Ted Harris, Associate Research Professor, Kansas Biological Survey & Center for Ecological Research, University of Kansas
Harris is one among 79 scientists from the international Global Lake Ecological Observatory Network (GLEON), examining processes and phenomena happening in freshwater ecosystems. Their new research shows that concentrations of plastic that can be seen in freshwater ecosystems are indeed higher than those seen in “garbage patches” in the ocean. The article was published in the journal Nature.
For his role, Harris collaborated with Rebecca Kessler, his former student, and recent KU graduate, to assess two Kansas lakes (Clinton and Perry) and the Cross Reservoir at the KU Field Station.
“That entailed us going out, tolling 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),” Kessler stated.
The research project was developed and coordinated by the Inland Water Ecology and Management research group of the University of Milano-Bicocca, Italy (led by Barbara Leoni and Veronica Nava). The group sampled surface waters of 38 reservoirs and lakes, circulated over gradients of limnological attributes and geographical position. It found plastic debris in all studied reservoirs and lakes.
This paper essentially shows the more humans, the more plastics. Places like Clinton Lake are relatively low in microplastics because—while there are many animals and trees—there aren’t a lot of humans, relative to somewhere like Lake Tahoe where people are living all around it. Some of these lakes are seemingly pristine and beautiful, yet that’s where the microplastics come from.
Ted Harris, Associate Research Professor, Kansas Biological Survey & Center for Ecological Research, University of Kansas
Harris stated that a majority of the plastics are from something as evidently innocuous as T-shirts.
“The simple act of people getting in swimming and having clothing that has microplastic fibers in it leads to microplastics getting everywhere,” he stated.
The GLEON study quotes two kinds of water bodies learned that are especially susceptible to plastic contamination: reservoirs and lakes in urbanized and densely populated areas; and those with raised deposition regions, long water retention durations, and high grades of anthropogenic influence.
“When we started the study, I didn’t know a lot about microplastics versus large plastics,” Harris stated.
“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. You don’t see a huge garbage patch in Lake Tahoe, yet it’s one of the most impacted lakes when it comes to microplastics. Those are plastics you can’t really see with the naked eye, and then you get underneath a scope at 40,000x, and you see these little jagged pieces and other particles that are the same size as algae or even smaller.”
Part of Harris and Kessler’s interest in participating in this project was to notify an area of the US that is usually ignored.
In this study, there’s one dot in the middle of the country, and that’s our sample. In Iowa, Missouri, and Colorado, there’s this huge swath of area that has water bodies, but we often don’t get them into those massive global studies. So it was really important for me to put Kansas on the map to see and contextualize what these differences are in our lakes.
Ted Harris, Associate Research Professor, Kansas Biological Survey & Center for Ecological Research, University of Kansas
Since 2013, Harris has worked at KU where his study concentrated on aquatic ecology. Kessler graduated from KU in 2022 with a degree in ecology, evolutionary, & organismal biology.
“The biggest takeaway from our study is that microplastics can be found in all lakes,” Kessler stated. “Obviously, there are different concentrations. But they are literally everywhere. And the biggest contributing factor to these microplastics is human interaction with the lakes.”
Journal Reference:
Nava, V., et al. (2023) Plastic debris in lakes and reservoirs. Nature. doi.org/10.1038/s41586-023-06168-4.