Microplastics Contamination in Lakes and Reservoirs a Threat to Freshwater Environments

Friday - July 14 2023, 00:12 UTC - 1 year ago

Researchers from the Global Lake Ecological Observatory Network have found that freshwater environments like lakes and reservoirs have a higher concentration of plastic than oceanic garbage patches, with human interaction identified as the main contributing factor. The research project was done by sampling surface waters of 38 lakes and reservoirs, and discovering plastic debris in all studied lakes and reservoirs. The two types of water bodies most vulnerable to plastic contamination are those in densely populated and urbanized areas and those with elevated deposition areas, long water retention times, and high levels of anthropogenic influence.

Research from the Global Lake Ecological Observatory Network finds that freshwater environments like lakes and reservoirs have higher concentrations of plastic than oceanic garbage patches, with human interaction identified as the main contributing factor. The study stresses the vulnerability of densely populated areas and water bodies with high human influence to plastic contamination.

Around 14 million tons of plastic end up in the ocean every year. But that is not the only water source where plastic represents a significant intrusion.

"We found microplastics in every lake we sampled," said Ted Harris, associate research professor for the Kansas Biological Survey & Center for Ecological Research at the University of Kansas. "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 one of 79 researchers belonging to the international Global Lake Ecological Observatory Network (GLEON), which examines processes and phenomena occurring in freshwater environments. Their new paper, titled "Plastic debris in lakes and reservoirs," reveals that concentrations of plastic found in freshwater environments are actually higher than those found in so-called "garbage patches" in the ocean. The article is published today (July 12) in the journal Nature.

For his role, Harris teamed with Rebecca Kessler, his former student and recent KU graduate, to test 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 said.

The research project was designed and coordinated by the Inland Water Ecology and Management research group of the University of Milano-Bicocca, Italy (headed by Barbara Leoni and Veronica Nava). The team sampled surface waters of 38 lakes and reservoirs, distributed across gradients of geographical position and limnological attributes. It detected plastic debris in all studied lakes and reservoirs.

"This paper essentially shows the more humans, the more plastics," Harris said. "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." .

Harris said that many of the plastics are from something as outwardly 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 said.

The GLEON study cites two types of water bodies studied that are particularly vulnerable to plastic contamination: lakes and reservoirs in densely populated and urbanized areas; and those with elevated deposition areas, long water retention times, and high levels of anthropogenic influence.

"When we started the study, I did not expect that we would find microplastics everywhere," said Brian T. McGrath, professor of ecology and environmental science at the American University of Beirut and lead author of the study.