A new study shows that lakes across Canada are playing host to high concentrations of a dangerous toxin that thrives in blue-green algae.
While the algae, also known as "pond scum," often serves as a disappointment to beach goers looking to cool off on a hot day, the accompanying toxin microcystin is also putting them and their children in danger, said Diane Orihel, lead author of the report.
"You and your children are at risk when you swim in a lake, when you Jet Ski, when you go boating, because you can inhale this toxin through your nose," Orihel, said.
Microcystin, which the researchers determined is most often present in bodies of water with a low nitrogen to phosphorous ratio, can stimulate the growth of cancer cells and even cause liver failure.
In their study, researchers looked at thousands of samples from 246 bodies of water in every province in Canada, collected between 2001 and 2011. They found microcystin levels ranging from undetectable, to the maximum measurable amount.
"Notably, all regions contained lakes where toxin concentrations reached levels of concern," the study said.
The highest concentrations were found in the Prairie provinces, particularly in clusters in central Alberta and southwestern Manitoba where lakes are often shallow and warm, with high concentrations of nutrients often due to agricultural runoff.
According to the study, 18 per cent of samples and 41 per cent of lakes exceeded the World Health Organization's drinking water guidelines.
The Canadian drinking water guideline was exceeded in 14 per cent of samples and 35 per cent of lakes.
And only 1.3 per cent of samples taken and 9 per cent of the lakes tested surpassed Canada's proposed guideline for recreational waters.
"In summary, our meta-analysis of microcystins in Canadian fresh waters has revealed that microcystins are now an issue of national concern, as these toxins were detected in every province, and concentrations exceeded water quality guidelines for drinking water, and sometimes for recreational waters, in many eutrophic ecosystems," the report said.
Orihel said rising levels of the toxin could eventually affect tourism, sport and commercial fishing if the situation is allowed to progress.
"In Lake Winnipeg what we've seen is an increase in the incidents of algae blooms and an increase in the intensity of algae blooms over the last 10 years," she told CTV Winnipeg.
Orihel is calling on governments across Canada to join forces and create a lake monitoring system across Canada.
With a report from CTV Winnipeg
