Members of the public are asked to avoid activities in Moscow’s Hordemann Pond after water samples taken from it confirmed the presence of two blue-green algae species at levels that exceed the recreational water quality threshold, Moscow Parks and Recreation Director David Schott said.

Idaho North-Central District Public Health, the Idaho Department of Environmental Quality and the city of Moscow on Monday issued a health advisory for the pond at Kiwanis Park in east Moscow, according to a city news release.

The two algae species, microsystis and dolichospermum, can potentially produce harmful toxins, Schott said.

He said the city asks that people avoid entering the water, fish in the water and to keep pets from the water.

According to the city’s news release, the following are the most common routes of exposure to cyanobacteria and their toxins during recreational activities: oral from accidental or deliberate ingestion of contaminated water; dermal by direct contact of exposed body parts with water containing cyanobacteria cells; and inhalation through the aspiration of water containing cyanobacteria and their toxins.

Health effects in humans may include abdominal pain, headache, sore throat, vomiting, nausea, dry cough, diarrhea, blistering around the mouth and pneumonia.

Blue-green algae are naturally occurring microscopic bacteria, the release states. Many species occur in Idaho surface waters and only some species release toxins under certain conditions.

Harmful algal blooms occur in water conditions of optimal temperature, oxygen and when nitrogen is unavailable and phosphorus is abundant. These circumstances are most common during the warmer months of late summer.

Schott said the city requested the sampling, which was conducted by IDEQ, because of public concern regarding the algae’s color.

He said the city will continue to monitor the situation and coordinate with IDEQ.

For more information, contact Schott at or (208) 883-7098.

Garrett Cabeza can be reached at (208) 883-4631, or by email to

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