All lakes have been contaminated by microplastics, scientists say

Photo: Pixabay/MolnarSzabolcsErdely

Microplastics pose grave threats not only to our health but to the environment as well. They are now everywhere down to the deepest recesses of the oceans.

They are also in all of our lakes, according to researchers at the University of Kansas and other institutions belonging to a team of scientists from the international Global Lake Ecological Observatory Network (GLEON).

Concentrations of plastic found in freshwater environments are actually higher than those found in so-called “garbage patches” in the ocean, they explain in a study.

In all, they sampled surface waters in 38 lakes and reservoirs across the planet and detected plastic debris in all the studied lakes and reservoirs.

“We found microplastics in every lake we sampled,” says Ted Harris, an associate research professor 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 and his colleague Rebecca Kessler tested 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,” Kessler says.

Anywhere people are, there is plastic pollution, the scientists say. That is why two types of water bodies are particularly vulnerable to plastic contamination: lakes and reservoirs in densely populated and urbanized areas.

“This paper essentially shows the more humans, the more plastics,” Harris says. “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.”

Many of the plastics now polluting lakes come from what seem like innocuous items.

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

“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,” Harris elucidates.

“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,” he adds.

The biggest takeaway from the research, Kessler notes, is that plastics “are literally everywhere. And the biggest contributing factor to these microplastics is human interaction with the lakes.”