Petri dish holds a mesh screen with various sizes of microplastics in it. Each piece of plastic looks either white or transparent.
Ryan Freeberg/Nevada Sagebrush. An example of microplastics extracted by the DRI microplastics lab. The research team first discovered microplastics in the waters of Lake Tahoe this past summer.

During the Desert Research Institute’s press conference at the American Geophysical Union in San Francisco, Calif. on Thursday, Dec. 12, the research group announced that they had discovered microplastics in the snow around the Lake Tahoe Basin. 

The report on the DRI’s findings was authored by Julia Mae Davidson, Monica M. Arienzo and Zoe Harrold. 

The findings are the first of their kind, as microplastics have never before been discovered in the snow around Lake Tahoe prior to this. 

Microplastics are defined by the DRI as plastic particles less than five millimeters in size. 

The research group made the discovery by collecting various snow samples from the Tahoe region and filtering the snow as it melted. Once the first level of filtration had completed, the team then filtered the contaminants into two groups.

The first group was comprised of pieces greater than 100 millimeters, followed by the second being divided by pieces ranging in size between 100 to 0.45 millimeters.

Once sizing on the contaminants was complete, they were sorted by shapes and colors.  

The predominant contaminant found among the pollutants were microfibers. Microfibers are fibers that have a diameter of less than 10 micrometers.

Prior to the announcement at the AGU, the DRI announced that they had discovered microplastics in the waters of Lake Tahoe.

Ryan Freeberg can be reached at and on Twitter @NevadaSagebrush.