It’s not just Californians and Nevadans who worship Lake Tahoe, the famous freshwater lake that straddles the border between their states. Snow or shine, visitors from all over flock to the shores of its clear blue waters, which are a little less fresh than they once were.

For the first time ever, microplastic particles were discovered in water samples taken from Lake Tahoe by the Desert Research Institute in Reno, Nevada. Since microplastics have been found to travel long distances via wind, rain, and snow, researchers are unsure where the plastics and synthetic fibers found in the samples originated, whether from one or more local, national, or global sources. The institute is currently conducting an investigation into the pollution and slated to share its findings with the American Geophysical Union this December.

Unfortunately, microplastics have been found in more and more remote locations recently, from the top of the Pyrenees to the Rocky Mountains, though less is known about their presence in alpine lakes like Tahoe, much of whose water comes from snowmelt. To find traces of plastic pollution in this or any other freshwater lake is an upset but, sadly, perhaps not a surprise.