This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The ubiquitous plastics of modern life are degrading into tiny fragments and littering Earth's landscapes and waterways. Scientists are starting to examine and measure this phenomenon to better understand how microplastics move through the environment and ultimately affect human and environmental health.
A new study focuses on the Truckee River, which stems from the clear blue waters of Lake Tahoe and traverses Reno and Sparks, Nevada, before reaching Pyramid Lake. The research sought to illuminate the concentrations and types of plastics accumulating throughout the river—which supplies drinking water to nearly half a million people. Published Sept. 15 in ACS ES&T Water, the research was led by Hannah Lukasik, a former master's student at DRI and the University of Nevada, Reno.
She was mentored by Monica Arienzo, director of DRI's Microplastics and Environmental Chemistry Lab. The group sampled microplastics at several sites upstream and downstream of Reno, Nevada, in fall 2022 and spring 2023. Microplastic concentrations were nearly 10 times higher in spring (mean 3.7 microplastics/liter) than in fall (mean 0.4 microplastics/liter), as higher spring flows likely flush them from the landscape and river bottom.
Polyethylene (used for things like plastic shopping bags, milk jugs and plastic wrap) and polypropylene (a sturdier plastic used for things like medical equipment, storage totes and automotive parts) were the dominant plastics identified. The research demonstrates that reducing single-use plastic throughout the Truckee River Basin is critical for protecting the river's water quality. "The Truckee River is such a critical artery for northern Nevada," Lukasik said.
"It not only supplies drinking water to around half a million people in the Reno–Sparks area, it's also a main water source for wildlife and is central to recreation in the region. Additionally, the river, terminating at Pyramid Lake, holds strong cultural and physical significance for the Pyramid Lake Paiute Tribe, which has called the lake home for generations." Understanding microplastic concentrations in rivers is important because rivers serve as both sinks and transport systems that can further degrade plastic fragments into even smaller pieces. Changes in seasonal flows can also determine where microplastics are distributed and how they settle into the soft sediments at river bottoms.
Identifying the interplay of these environmental factors is critical for informing modeling and remediation efforts. The research team selected nine sampling sites between the river's headwaters at Lake Tahoe and downstream of the Reno–Sparks metro area. The sites were selected to capture both upstream and downstream locations of major population centers, wastewater treatment centers and river confluences.
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