‘Extremely high levels’ of toxic algae confirmed at Summit Lake

Thurston County Environmental Health officials are warning people and pets to stay away from Summit Lake.

Tests confirmed that a blue-green algae bloom on the northwest Thurston County lake is producing “extremely high levels” of the toxin Anatoxin-a, a neurotoxin, according to Thurston County Environmental Health.

A sample taken last week was at 354 micrograms per liter, while just 1 microgram per liter is reason for concern, officials say.

Anatoxin-a is a potent toxin that affects the nervous system. Symptoms include lethargy, muscle aches, confusion and memory impairment, according to the state’s freshwater algae bloom monitoring program. If the concentration is high enough, it can cause death, officials say.

“Public Health will continue to monitor the situation, and will take more lake samples in the next week,” stated a news release the county issued Monday.

“They will continue to update residents. They ask that residents share information with their neighbors and get the word out.”

Because some residents in the area use lake water as their potable water source, the county issued a blue-green algae advisory on the lake Friday, after the algae bloom was confirmed but before test results on the toxin levels were available.

At this time, residents and lake users should not:

▪ Drink water taken from the lake until laboratory tests show the water is safe. Disinfection, boiling and treatment systems do not remove or deactivate algae toxin.

▪ Shower in water taken from the lake.

▪ Fish, swim or otherwise be in contact with the water.

▪ Allow pets and children near the water.

For more information on the advisory, call Jane Mountjoy-Venning at 360-867-2643.

This story was originally published May 9, 2017 at 7:47 AM with the headline "‘Extremely high levels’ of toxic algae confirmed at Summit Lake."