Heat wave may have left a toxic legacy

small pond full of cyanobacteria
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The heat wave from earlier this month could pose a lingering and deadly danger to your children, livestock, or pets — blue-green algae.

The algae contains several types of toxins, which can cause organ damage; affect the nervous and respiratory systems; cause paralysis; and, in extreme cases, can kill. While people are not likely to drink the foul-smelling water, young children can be at risk. You can also be exposed to blue-green algae from swimming, boating, or waterskiing.

Blue-green algae blooms are more likely to occur during a heat wave but they can last for weeks or months. Wind can worsen the problem, by pushing the algae into concentrated pockets.

Provincial officials say the first step is to identify a potential bloom — it can look like “blue-green scum, pea soup, or grass clippings suspended in the water.” If you can grab a solid mass of the algae in your hand, it’s likely not blue-green algae, officials say.

If you suspect the algae is in your dugout or other body of water on your farm, remove livestock from the water source, ensure children can’t access it, and consult a water specialist.

If blue-green algae is present, the dugout can be treated using a copper product registered for use in farm dugouts, provincial officials say.

“Once you treat it, consumption should be restricted for up to a month,” agricultural water engineer Shawn Elgert said in a release. “The use of copper will break the cells open and release the toxins if present into the water all at once. So it’s important that you stop using the water during this time so the toxins can degrade.

“You can follow up with aluminum sulphate and/or hydrated lime treatments afterwards to remove the nutrients from the water to prevent regrowth.”

There are also preventive measures to lessen the likelihood of blue-green algae blooms, such as a deeper dugout with slopes that are not too flat. Buffer strips and grassed waterways are recommended to reduce the amount of nutrients entering a dugout. (The province has a guide to building dugouts at www.agriculture.alberta.ca)

But blooms can occur in any water body that is shallow or has slow moving or still water, including freshwater lakes, ponds, or wetlands.

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