A health advisory was issued today for Avondale Lake in Hayden by the Panhandle Health District and the Idaho Department of Environmental Quality. Water samples confirmed the presence of the blue-green algae, which can produce potentially dangerous toxins.

People recreating near Avondale Lake are advised to avoid swallowing or inhaling water and to avoid direct contact with water containing visible algae. Drinking water from the lake is especially dangerous and the toxins cannot be removed by boiling or filtering the water. Consuming water containing high levels of blue-green algal toxins has been associated with effects on the liver and on the nervous system. Children and pets are particularly susceptible. If people choose to eat fish from this area, it is recommended that you remove all fat, skin and organs before cooking since toxins are more likely to collect in those tissues.

Blue-green algae are naturally occurring, microscopic bacteria. The physical appearance of blue-green algae blooms can be unsightly, often causing thick green mats along shorelines. Many species occur in Idaho surface waters and only some species release toxins under certain conditions. Harmful algae blooms occur in water conditions of optimal temperature, oxygen, and when nitrogen is unavailable and phosphorus is abundant. Often excess nutrients associated with algae blooms are caused by pollution from human activities. These circumstances are most common during the warmer summer months.

This is the second lake in Kootenai County with confirmed presence of blue-green algae in 2015. The health advisory for Fernan Lake is still active at this time.

The public will be advised when the concern no longer exists. Water quality improvements can be expected to reduce future algae blooms so the Idaho Department of Environmental Quality is working with residents and landowners to implement nutrient reduction projects.