Snowstorms are carrying microplastics onto remote Sierra Nevada terrain, including sites reachable only on skis, according to a new UC Riverside study in the journal Environmental Science and Technology.
Why it matters: The Sierra snowpack supplies about 30% of California's fresh water, UC Riverside said. The study did not measure how much plastic reaches drinking water or assess health effects.
What they found
- Lead researcher Aleksandra Karapetrova collected 43 samples from seven sites and found plastic at every one, the Los Angeles Times reported.
- Remote sites received 267 to 3,190 particles per square meter per day during storms; a station near Mammoth Mountain got about three times as much, 2,560 to 7,480.
- Snow after a 28-day dry spell held about 69 particles per liter of meltwater, versus about 11 after four dry days, because storms "scrub" plastic that builds up in the air.
- The most common plastics were polyethylene, polypropylene and polyester, used in clothing and packaging.
Air-mass tracing showed most storm air passed over Fresno and Madera counties, suggesting the Central Valley contributes, though models could not pin down exact sources. Snowfall deposited about 7.5 times more plastic per day than dry weather.