Lake Tahoe's famously clear blue water is facing renewed scrutiny after earlier research found that it ranked third among lakes studied for microplastic concentrations. Now, scientists in Nevada are taking a closer look at how much of the pollution is in the popular lake — and what that could mean for the people and wildlife that rely on it.

What's happening?

Researchers at the Desert Research Institute and the University of Nevada, Reno are studying microplastics in Lake Tahoe, including particles smaller than 20 microns — tiny pieces of plastic that are much harder to detect and understand, the Tahoe Daily Tribune reported.

Microplastics are generally defined as plastic particles ranging from about 5 millimeters down to 1 micron, according to DRI associate research professor Monica Arienzo. In other words, they can be as large as a pencil eraser or as small as bacteria.

The new work builds on an earlier global study that found Lake Tahoe had the third-highest microplastic concentration among the lakes included in that analysis. UNR research assistant professor Carina Seitz said the goal now is to track how bigger plastic pieces degrade into tinier bits and what that means for the lake's ecosystem, according to the Daily Tribune.

Researchers are especially focused on the tiniest particles because they may pose a greater risk to people. UNR associate professor of public health Li Li said these smaller plastics may enter the human body more easily than larger ones and may remain there longer.

"They can go with the blood and circulate throughout your body, reaching every corner. And because they are so small, they have the chance to go through barriers, like the blood-brain barrier, and when they get there, they will stay in your brain, and there is no way for you to get rid of them," Li said.

Li noted that the levels measured in Tahoe's water are not high enough to raise major human exposure concerns, even though the lake serves as a drinking water source. Still, he said the chemicals microplastics may carry are a bigger concern.

Why is Lake Tahoe's microplastics problem important?

Lake Tahoe is more than a scenic destination. It is a critical freshwater resource, a major tourism driver, and a source of pride for surrounding communities. Pollution in the lake threatens all of that.

One challenge with microplastics is that they become harder — and eventually nearly impossible — to remove once they break down into extremely small pieces. That means every bottle, wrapper, or plastic fragment left behind can turn into a longer-lasting problem for the water, shoreline, and food web.

There are also still major unanswered questions about health effects. Even if Tahoe's current measured levels are not considered an immediate danger, the findings add to broader concerns about how widespread plastic pollution has become in waterways that people depend on for drinking water and recreation.

Cleaner water supports public health, outdoor recreation, and wildlife habitat. If microplastic pollution continues to build, protecting all three could become more difficult.

What's being done about Lake Tahoe's microplastics problem?

Researchers say one of the biggest solutions is also one of the simplest: use less plastic in the first place.

Arienzo said she does not think recycling alone will solve plastic pollution and argued that reducing plastic use is the most effective way to keep microplastics out of waterways.

South Lake Tahoe has already taken a step in that direction. In April 2024, the city banned single-use water bottles for commercial vendors. Laura Patten, natural resources director at Keep Tahoe Blue, said cleanup crews have already found fewer plastic water bottles.

Keep Tahoe Blue is also working with ECO-CLEAN Solutions to use a cleaning robot called BEBOT to remove plastic buried in sand that volunteers may miss. 

Residents and visitors are also urged to make sure they don't leave any trash behind, particularly during big events such as the Fourth of July, when lake shoreline pollution hits all-time highs.

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