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Spokane, Washington  Est. May 19, 1883

More than 600 pieces of plastic found polluting popular Lake Tahoe areas, new study finds

A view of Lake Tahoe from Emerald Bay State Park in South Lake Tahoe in July. Scuba divers involved in a recent research study found 673 pieces of plastic in the lake at five different locations, raising pollution concerns.  (Hector Amezcua/The Sacramento Bee/TNS)
By Molly Jarone Sacramento Bee

The world’s largest alpine lake and a California jewel is being littered with plastic.

In a study published late last year in the journal Applied Spectroscopy, scuba divers found 673 pieces of plastic in the lakebed of Lake Tahoe at five different locations, raising concerns about the extent of plastic pollution across the lake.

Researchers found that the greatest source of pollution was degraded pieces of plastic followed by food containers, bottles, plastic bags and toys.

The highest concentrations of plastics were found in recreation areas such as Hidden Beach and South Sand Harbor. These areas are heavily frequented by beach goers and are known for being rocky, which scientists said may trap litter. Food containers accounted for 27% of the litter at South Sand Harbor and 19% at Hidden Beach, according to the study results. Scientists also collected data from Nevada Beach, East Incline and Zephyr Cove that indicated plastic pollution.

“We recommend that education on proper disposal of food containers, plastic bags, toys, and bottles would help to reduce the plastic litter entering Lake Tahoe,” the study said.

The recent study was conducted by researchers with the Tahoe Environmental Research Center at UC Davis as well as the Nevada-based Desert Research Institute.

A study of Lake Tahoe’s clarity in 2022 also raised concerns about plastic pollution in the lake water.

In 2022, the lake showed levels of microplastic abundance at all levels of the lake “to be some of the highest reported among North American lakes,” according to the 2022 Lake Tahoe Clarity report. The researchers went on to say that the amount of microplastics “found at Tahoe approach those measured in San Francisco Bay.”

“What goes into Tahoe, stays in Tahoe,” Geoffrey Schladow, director of the Tahoe Environmental Research Center at UC Davis, said at the time. “It’s a worry for every aquatic system.”

Despite the rise in plastic pollution, the clarity of Lake Tahoe was among the best recorded in the last 30 years.

In the second half of 2022, “Lake Tahoe was the clearest it has been since the 1980s,” according to the report, which said clarity reached nearly 72 feet using a Secchi disk to measure visibility in the iconic waters. The Secchi disk is a 10-inch, round white disk that is lowered into the lake to measure the deepest possible clarity.

The improving clarity was a sharp turn from just five years ago in 2017, the murkiest year in recent memory. Clarity only marginally improved by 2021, when scientists recorded the second-worst clarity reading on record at a depth of 61 feet.