Blue Green Algae Poisoning Frequently Asked Questions

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 What is blue green algae poisoning?
Blue green algae are single cell cyanobacteria that produce a microcystin toxin. Removing animals from affected areas is the only fail-proof method of preventing poisoning.

Where does blue green algae develop?
The algae thrive in warm stagnant water that is high in nitrogen and phosphate. The colonies can be individual and appear as if there are grass clippings in the water, or can accumulate and looks like a paint slick on the top of the water, or as mud like masses along shorelines. A strong smell may be present. The scum may appear and disappear over a period of days.

Winter survival of the algae is possible with the resting form of the bacteria settling to the bottom of the water body and re-emerging the next spring.

How does the toxin effect livestock?
Some species of cyanobacteria produce a nerve inhibitor (alkaloid) that prevents nerve impulse transmission. Muscle twitches, scouring, photosensitivity, and loss of coordination are early symptoms. If sufficient quantities of the toxin are consumed, paralysis and respiratory failure occurs rapidly. Animals are not able to breathe and suffocate to death within minutes thus animals are usually found close to the suspect water source.

Other species of bacteria cause liver damage to occur when polypeptide toxins are produced. Death will occur up to 36 hours after consumption. More animals survive this form of poisoning but survivors have metabolic problems that can last for months.

The largest release of toxin occurs when blue green algae dies. Cooler weather, rainfall and windy conditions can kill blue green algae.

Can humans be affected by blue green algae?
Yes, if you suspect blue green algae, avoid direct skin contact or consumption of suspect water. Do not take samples without using rubber gloves or a dipping cup. Minor contact can cause abdominal pain with vomiting, diarrhea, rashes, eye irritation, and allergic reactions. In very severe cases, liver injury and death can occur.

How can areas be treated to control blue green algae?
Treatment of water with copper sulfate controls algal bloom when applied at 1/4 to 1/2 pound per 100,000 gallons of water. Do not allow animals to drink water from treated areas for 3 weeks. Blue green algal blooms that wash up on the shore and dry out can be toxic for up to 5 months.

Managing Phosphorus to Protect Water Quality
A Primer on Water Quality: Agricultural Contaminants - Background Information
Treatment of Dugouts
Water Quality Treating for Blue Green Algae
Aeration to Control Blue Green Algae
Best Management Practices to Minimize Blue Green Algae
Cyanobacterial Blooms in Surface Waters
Cyanobacterial Toxicity
Impact of Blue Green Algae on Human Health

Prepared by Barry Yaremcio, Ag- Info Centre, Alberta Agriculture and Rural Development

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For more information about the content of this document, contact the Ag-Info Centre.
This information published to the web on August 6, 2003.
Last Reviewed/Revised on May 5, 2015.