Early in the morning on Lake Tahoe, locals listen to the sounds of waves and birds chirping as the morning sun catches the sparkling water. The clean water has also attracted international attention.
But ongoing research in collaboration with the Desert Research Institute (DRI) and the University of Nevada, Reno (UNR) may reveal just how much microplastics pollute once pristine lakes.
Monica Arienzo, an associate research professor in the Department of Hydrology at the Desert Research Institute, defined microplastics as particles as small as 5 millimeters to 1 micron.
“So it’s basically the size of a pencil eraser…all the way down to the size of bacteria,” Arienzo said.
Arienzo said microplastics come from a variety of sources that are difficult to identify.
“Well, in our research, we’re very interested in understanding the sources. And where are the sources? Where are these plastics in the environment? And where do they go in the environment?” Alienzo said.
Karina Seitz, research assistant professor in UNR’s Department of Biology, said previous work paved the way for the current study.
“There was one study in particular that evaluated microplastics around the world, and Lake Tahoe was one of those lakes, and it was found that Lake Tahoe was the third lake with higher concentrations of microplastics,” Seitz said.
She said her research complements existing research and aims to understand how large plastic debris breaks down into smaller particles and how this affects lake ecosystems.
What makes this study unique is that it focuses on microplastics smaller than 20 microns. Particles of that size may be nearly invisible to the naked eye or require a microscope to see.
Li Li, an associate professor of public health at UNR, said it is essential to study microplastics smaller than 20 microns to understand their potential human health effects.
“Measuring these very small microplastics is very important for us because compared to larger microplastics, they are more likely to enter the human body and more likely to remain there for longer,” Lee said.
Once microplastics enter the human body, they circulate throughout the body.
“They circulate through the body with the blood and reach every part of the body. And because they’re so small, they can cross barriers such as the blood-brain barrier. And once they get there, they stay in the brain and there’s no way to get rid of them,” Lee said.
But Lee said he’s not immediately concerned, even though Lake Tahoe is a source of drinking water.
“The levels found in Lake Tahoe water are too low to cause significant exposure to humans. My personal understanding is that the levels found so far are not high enough to cause public concern for the Reno area,” Lee said.
Lee said research has shown that microplastics in the human body do not necessarily indicate an immediate health problem, and the public may be misunderstood.
Of further concern to Lee are the chemicals that microplastics can carry.
“When you ingest microplastics, you’re also introducing these chemicals into your body. So this is common with pesticides.[You]use pesticides separately from plastics, right? But when they get into the environment, they tend to combine with each other,” Lee said.
He said long-term studies are needed to understand the health effects of microplastics.
Arienzo said there is one big solution to the plastic pollution problem.
“I strongly believe that recycling is not an issue with this plastic pollution problem. I believe that the best thing we can do to reduce plastic pollution and microplastics in our waterways and environment is to eliminate the use of plastics,” Arienzo said.
The City of South Lake Tahoe banned the sale of single-use water bottles to commercial businesses in April 2024.
Laura Patten, natural resources director for Keep Tahoe Blue (KTB), has seen the impact of the ban firsthand.
“As we’ve been conducting clean-up operations, we’ve seen fewer plastic water bottles. We continue to collect information and data on the effectiveness of these bans, but what we’ve seen is really positive progress,” Patten said.
Part of the effort is installing water stations around South Lake Tahoe and educating nearby businesses about the policy, Patten said.
KTB is also working with ECO-CLEAN Solutions to use a cleaning robot called BEBOT. Plastics that are trapped under the sand and not picked up by volunteers can be removed.
With BEBOT and volunteer cleaning days, KTB prioritizes prevention.
“One of the problems is that if you don’t capture microplastics before they break down, it’s really impossible to remove them,” Patten said. “So we’ve focused on cleaning, understanding cleaning, and policy and advocacy to ensure that plastic never enters Tahoe’s environment.”
Given the current outlook for plastic pollution in Lake Tahoe, Seitz remains positive throughout his research.
“I feel optimistic. I think people can make big changes if they want to. I strongly believe there are always alternatives to progress and development in a way that is safe for the environment and for health,” Setis said.
