U of R study underlines toxicity of algae in lakes
First Nations, municipalities draw water from Qu’appelle River drainage basin
Water researchers at the University of Regina are using the results of their 11-year study in south Saskatchewan to conclude increasing algae blooms in the area’s lakes are putting out more toxins that could be harmful to humans.
Working out of the U of R’s Institute of Environmental Change and Society, the group of four researchers studied from 2005 to 2016 the following lakes: Buffalo Pound, Last Mountain, Pasqua, Katepwa, Crooked and Wascana. The area, called the Qu’appelle River drainage basin, covers 52,000 square kilometres, or roughly 40 per cent of south Saskatchewan; that’s about 89 per cent of Lake Michigan’s surface area in size.
The group says global warming, urban growth and spring run-off from farm fertilizers have increased pollution levels of the lakes’ fresh waters; that pollution has increased the growth of bluegreen algae (also called cyanobacteria), which produces microcystin, a cancer-causing toxin.
“That’s the trifecta that interacts to really degrade the surface waters in Saskatchewan, at least in southern Saskatchewan,” said the study ’s designer, Peter Leavitt.
To the naked eye of the regular boater, fisher or wake-boarder, such algae can appear in one of three ways, he said.
“They’re the kind of green scum that you see floating on the lakes. Sometimes it looks like somebody poured a can of paint on them; those are the really toxic ones. Sometimes it looks like someone emptied their lawn-mower clippings bag into the lake, (like) there’s little shards of grass, and those too are toxic. Then there’s other times where the lake will look a little bit grey.”
Leavitt believes those algae produce microcystin as a deterrent, “like a chemical warning: ‘Stay away from me, I’m toxic. If you ingest me, I’ll be bad for you.’ ” It’s hepatotoxin, he said, meaning it will damage an organism’s liver.
“It doesn’t get through the (human) gut wall, the intestinal lining very well, but if it does, it’s quite lethal. If you actually got it in your bloodstream, it would be like getting a dose of cyanide. It’s got a higher molecular-toxicity than cyanide,” Leavitt said.
Humans tend to pass the toxin through their systems, he said, however the key is to avoid chronic exposure to microcystin.
Cattle are more susceptible to the toxin, because of their complicated, five-chamber digestive tracts, he said.
Unlike cattle drinking from a lake or dugout covered with algae, humans aren’t likely to be gulping down such water, at least not on purpose with regularity, Leavitt said.
But he highlighted the study’s relevance to municipalities and First Nations that all draw their water from the Qu’appelle River drainage basin: Moose Jaw, Regina, Lumsden, Pasqua First Nation, Muscowpetung First Nation and Cowessess First Nation.
Pasqua First Nation Chief Todd Peigan commended Leavitt’s team for informing him of their work and their findings. “It confirms what we’ve been telling the Saskatchewan Watershed Authority on the state of the Qu’appelle water.”
Peigan said Pasqua doesn’t draw its drinking water from the adjacent Pasqua lake on its north side; “we draw our water from the Hatfield Valley Aquifer,” underneath Pasqua’s land.
The 11-year U of R study makes him wonder about the water quality there. “If we’re on the Hatfield Aquifer, the Pasqua Lake sits near and/or above the aquifer, and if the Pasqua Lake waters are a tributary to that aquifer, then the aquifer would be impacted,” Peigan said. “Thereby impacting human consumption. That’s a more in-depth study that has to be taken.”