Friday, June 09, 2023

Health advisories issued for Avondale Lake and Morton Slough

| August 20, 2022 1:00 AM

Health advisories were issued Friday for Avondale Lake near Hayden and Morton Slough in Sagle.

The advisories are based on recent water sampling that indicates the presence of cyanobacteria, also known as harmful algae bloom or blue-green algae, and they were issued by Panhandle Health District in collaboration with the Idaho Department of Health and Welfare and the Idaho Department of Environmental Quality.

The public is urged to use caution when recreating in or near the water, especially where ingestion is a risk.

Cyanobacteria are a natural part of Idaho’s water bodies. When temperatures rise, their populations can bloom and toxic chemical compounds, or cyanotoxins, can be released into the water. Caution should be taken anywhere where the water appears discolored or murky as harmful algae blooms can spread or move with wind and water currents.

These algae blooms have the potential to produce dangerous toxins especially when accumulated in high concentrations. The physical appearance of these blooms can be unsightly, often presenting as discolored water, streaks or globs of scum and causing thick green mats along lake shorelines.

Pets, children, the elderly and people with compromised immune systems are most at-risk of harmful exposure.

Anyone recreating in Avondale Lake or Morton Slough is advised to take precautions to avoid exposure to lake water appearing to contain a harmful algae bloom.

Private domestic water system owners using the lake as a drinking water source are cautioned that potentially present toxins cannot be removed by boiling or filtering the water. If contact (swimming, bathing or showering) has been made with water containing a harmful algae bloom, it is recommended to wash off with fresh water.

If people choose to eat fish from the lake or slough, it is recommended they remove all fat, skin and organs before cooking, since toxins are more likely to collect in those tissues.

Symptoms of exposure to algal toxins vary according to exposure. Symptoms include rashes, hives, diarrhea, vomiting, coughing and/or wheezing. More severe symptoms affecting the liver and nervous system may result from ingestion of water. If symptoms persist, consult with your health care provider.

For more information about harmful algal blooms, visit DEQ’s website at or IDHW’s website at

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