In the early morning at Lake Tahoe, locals hear waves crashing and birds chirping as the glistening water catches the emerging sun. The pristine water even attracts international attention.
However, ongoing research in collaboration with the Desert Research Institute (DRI) and the University of Nevada, Reno (UNR) might reveal how much microplastics are polluting the once pristine lake.
Monica Arienzo, an associate research professor in the division of hydrologic sciences at the Desert Research Institute, defined microplastics as particles ranging from five millimeters to as small as one micron.
“So that's basically like the size of a pencil eraser … down to about the size of bacteria,” Arienzo said.
Microplastics originate from various sources that are difficult to identify, Arienzo said.
"So yeah, in our research, we are really interested in understanding sources, and then also, where are they? Where are these plastics in the environment? And where are they going in the environment?” Arienzo said.
Carina Seitz, research assistant professor in the department of biology at UNR, said that a previous study has paved the way for her current research.
“There was one study in particular that assessed microplastics around the world. And Lake Tahoe was one of these lakes, and they found that Lake Tahoe was the third lake with a higher concentration of microplastics, ” Seitz said.
She said her research aims to complement existing studies and to understand how larger plastic fragments break down into smaller particles and how that affects the lake’s ecosystem.
What sets this research apart is the focus on microplastics smaller than 20 microns. A particle of that size may be barely visible to the naked eye or require a microscope to see.
Li Li, an associate professor of public health at UNR, said that researching microplastics below 20 microns is vital to understanding potential human health impacts.
“It's very important for us to measure these very small, very tiny microplastics, because compared to the larger ones, they are more likely to get into the human body and more likely to stay there for a longer time,” Li said.
Once microplastics enter the human body, they circulate throughout the system.
“They can go with the blood and circulate in your body and reach every single corner of your body. And because they are so small, they have the chance to go through barriers, like the blood-brain barrier,” Li said, “and when they get there, they will stay in your brain, and there is no way for you to get rid of them.”
However, Li said he isn’t immediately concerned about Lake Tahoe despite it being a source of drinking water.
“The level we find in the Lake Tahoe water is too low to cause significant exposure to human beings. My personal understanding is the level we find so far is not enough to trigger public concern over the Reno area,” Li said.
Research finds that microplastics in the human body don't necessarily indicate immediate health issues, which the general public may misunderstand, according to Li.
What is more concerning to Li is the chemicals that microplastics may carry.
“When you take the microplastics, you also take these chemicals into your body. So this is very common for pesticides. [You] use a pesticide separately from the plastics, right? But when they get into the environment, they tend to combine with each other,” Li said.
He said that understanding the health impacts of microplastics requires long-term studies.
Arienzo said that the plastic pollution issue has one major solution.
“I'm a big believer that we will not recycle our way out of this problem of plastic pollution. I believe that the best thing we can do to reduce plastic pollution and microplastics in our waterways, in our environment, is to eliminate the use of plastics,” Arienzo said.
The City of South Lake Tahoe banned single-use water bottles for commercial vendors in April 2024.
Laura Patten, the natural resource director at Keep Tahoe Blue (KTB), has seen the effects of the ban firsthand.
“We've been finding less [sic] plastic water bottles when we do our cleanups. We're still continuing to collect more information and data on the efficacy of these bans, but what we've seen is really some positive progress,” Patten said.
Installing water refill stations around South Lake Tahoe and educating nearby businesses about the policy are part of the effort, said Patten.
In collaboration with ECO-CLEAN Solutions, KTB also uses a cleaning robot called BEBOT. It’s able to remove plastic trapped under the sand and not picked up by volunteers.
With the BEBOT and volunteer clean-up days, KTB prioritizes prevention.
“One of the issues is, if you don't capture microplastics before they break down, they're really impossible to remove,” Patten said, “So we've really focused our efforts on cleanups, understand cleanings, and then policy and advocacy around preventing plastics from ever coming into Tahoe's environment."
With the current outlook of plastic pollution in Lake Tahoe, Seitz remains positive through her research.
“I feel optimistic. I think that people can do [sic] great changes if they are willing. I am a strong believer that there are always alternatives to have progress and development in a way that is safe for our environment and for our health,” Setiz said.
