What do Blue-green Algae advisories mean for beach-goers?

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As the summer heats up, Albertans have already been handed five blue-green algae advisories and there will, unfortunately, be several more in the coming weeks (update: more than 20 as of August 8th). What do these advisories mean for beach-goers, swimmers, and recreational water users?

Up until 2015, the blue-green algae advisories issued by Alberta Health Services advised against swimming in any lake that was undergoing a bloom. Several years of water monitoring have demonstrated that these guidelines exceeded the necessary level of caution.

The new rule of thumb is to avoid swimming wherever a blue-green algae bloom is visible. Blooms will often appear only in part of a lake and depending on environmental conditions and wind patterns, a bloom can also move from one part of the lake to another. In general, it is safe to swim as long as the telltale green scum is not visible. Blue-green algae normally appear close to the surface of the water, but keep in mind that if it is windy, the wave action can drive the algae deeper making it more difficult to see.

Unfortunately, if an advisory has been posted, it will generally remain for the rest of the season. The good news is that you can still swim if part of the lake is clear.

Always check the water before entering and if you see a bloom, please report it to your nearest Environmental Health Office. For more information read the Alberta Health Services advisory below.


A typical advisory from Alberta Health Services looks like this:

“Residents living near the shores of this lake, as well as visitors to this lake, are advised to take the following precautions:

  • Avoid all contact with blue-green algae (cyanobacteria) blooms.  If contact occurs, wash with tap water as soon as possible.
  • Do not swim or wade (or allow your pets to swim or wade) in any areas where blue-green algae (cyanobacteria) is visible.
  • Do not feed whole fish or fish trimmings from this lake to your pets.
  • Consider limiting human consumption of whole fish and fish trimmings from this lake, as it is known that fish may store toxins in their liver.  (People can safely consume fish fillets from this lake).

As always, visitors and residents are reminded to never drink or cook with untreated water directly from any recreational body of water, including Isle Lake, at any time. Boiling of this water will not remove the toxins produced by blue-green algae (cyanobacteria). An alternate source of drinking water should also be provided for pets and livestock, while this advisory is active.

Blue-green algae (cyanobacteria) is naturally occurring, and often become visible when weather conditions are calm.  Appearing like scum, grass clippings, fuzz or globs on the surface of water, blue-green algae (cyanobacteria) can be blue-green, greenish-brown, brown, and/or pinkish-red, and often smell musty or grassy.

People who come in contact with visible blue-green algae (cyanobacteria), or who ingest water containing blue-green algae (cyanobacteria), may experience skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea and vomiting and/or diarrhea. Symptoms usually appear within one to three hours and resolve in one to two days. Symptoms in children are often more pronounced; however, all humans are at risk of these symptoms.

Weather and wind conditions can cause algae blooms to move from one location in the lake to another.  As such, this advisory will remain in effect for Isle Lake, until further notice.

Please note that areas of Isle Lake in which the blue-green algae (cyanobacteria) bloom is NOT visible can still be used for recreational purposes, even while this Blue-green Algae (Cyanobacteria) Advisory is in place.

If you suspect a problem related to blue-green algae (cyanobacteria), or if you require further information on health concerns and blue-green algae (cyanobacteria), please call Health Link at 811. Additional information is also available online, at www.ahs.ca/bga.

Alberta Health Services is the provincial health authority responsible for planning and delivering health supports and services for more than four million adults and children living in Alberta. Its mission is to provide a patient-focused, quality health system that is accessible and sustainable for all Albertans.”

source: http://www.albertahealthservices.ca/news/Page13928.aspx

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