Toxic algae detected in some Tahoe Keys waterways | TahoeDailyTribune.com

Toxic algae detected in some Tahoe Keys waterways

Signs warning of potentially harmful algae blooms were posted in certain areas within the Tahoe Keys earlier this week.

Residents and visitors in certain areas of the Tahoe Keys are being warned of the presence of potentially poisonous algae.

Warnings were posted earlier this week along specific waterways, including off Aloha Drive. The signs say harmful algae may be present in the water. As of Friday, all the samplings tested so far indicated the lowest possible level of toxins, Greg Hoover, water quality manager and aquatic invasive species management coordinator for the Tahoe Keys Property Owners Association (TKPOA), told the Tribune Friday.

However, toxin levels can fluctuate up and down for many reasons, some unknown to water managers.

"The toxin level can go up and down based on all sorts of factors, a lot based on factors we don't even understand," Doug Smith, supervising engineering geologist with the Lahontan Water Board, told the Tribune Friday.

The caution signs posted in areas of the Keys recommend staying away from algae and scum if swimming in the water and keeping children away from the algae altogether. The water should not be used for cooking or drinking, and pets should be kept away from the water and any algae that may wash onto land.

Blue-green algae is naturally occurring and its presence has been increasingly noticed in bodies of water throughout California. Back in July water officials issued a warning telling people in Los Angeles County to avoid contact with water in Pyramid Lake due to a bloom of toxic blue-green algae.

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Only certain forms of the algae produce toxins, Smith said. As far as the level of risk posed to people in the Keys, Smith added, "They should be aware of this because it's happening all across the state, and they should exercise caution … and try not to drink gobs [of the water]."

Reports of potentially harmful blue-green algae first came in on Aug. 19, according to Lahontan.

In the normal process, the water board would act as the first responders and take water tests and send them to a lab. However, Smith said TKPOA expressed a desire to fast-track the process.

Staff from the TKPOA collected three water samples from the main lagoon on Monday, Aug. 21, and paid to have those samples sent to the lab faster than would normally be the case, Smith said.

Those lab results, which were received Thursday, Aug. 24, showed low levels of Anatoxin-A and microcystins were present in some of the water samples.

Lahontan Water Board staff conducted a site visit throughout the main channel and collected water samples from lagoon waters adjacent to properties on Aloha, Lido and Morro drives on Tuesday, Aug. 22. Those sample results are expected sometime this coming week.

From there, water board staff and other officials will work together to monitor the situation. Representatives from other agencies, including El Dorado County Public Health, the Tahoe Regional Planning Agency (TRPA) and others, have been alerted of the situation.

"TRPA is aware of this concerning development and working closely with the Lahontan Water Board, who has jurisdiction on this matter, to monitor the situation and make sure that appropriate steps are taken to protect public health, safety, and the environment," Tom Lotshaw, public information officer for TRPA, said in an emailed statement.

Continued assessment of the situation will likely involve daily visual monitoring and sampling once per week, especially if favorable conditions continue, according to Lahontan.

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