“A pea soup in water”: a quick test to detect blue-green algae

Thanks to a lake’s DNA analysis tool, Quebecers will soon be able to know in real time if their lake is contaminated by blue-green algae.

Should we avoid swimming when an episode of cyanobacteria (blue-green algae) is observed? However, Currently, many residents do not know on what foot dancing, because the ministry analyzes, when there are, take time.

“The way to detect cyanobacteria. For example, in the laboratory, is really long, it is done under a microscope and it takes four days so it is too late to intervene,” explains Stéphanie Lord-Fontaine, vice-president of Genome Quebec.

At Lake Maskinongé. Therefore, in Lanaudière, each episode of cyanobacteria leads to the complete or partial closure of the municipal beach. Meanwhile, “We cannot take chance,” explains Daniel Coulombe, president of the friends of Lake Maskinongé in Lanaudière. In addition, It takes too “a pea soup water”: quick long to get the results. Furthermore, ”

However, it is crucial to know if the observed cyanobacteria produce toxins.

“When there are toxins and they find themselves in the water, this is called the efflorescences. Meanwhile, It’s like pea soup and we don’t bathe, ”adds M^me Lord-Fontaine.

Less surveillance

Since 2018, surveillance of cyanobacteria in Quebec has been reduced to the bare minimum. The ministry no longer publishes an annual assessment and does not systematically move in the field.

For the year 2024-2025. despite 197 reports, only seven bodies of water were inspected and four cases of cyanobacteria efflorescences were confirmed.

In comparison. in 2007, 275 lakes had been inspected and efflorescences of cyanobacteria had been reported for 167 of them, according to data from the ministry.

The answer in DNA

A pilot project from the National Institute for Scientific Research (INRS). Laval University could change the situation. Researcher Jérôme “a pea soup water”: quick Comte has developed a tool capable of detecting cyanobacteria from a simple DNA sample in just a. few hours. Mr. Comte’s team is currently working on improving toxins analyzes in different cyanobacteria.

Thanks to the financial support of the non -profit scientific organization genome Quebec. the technology made it possible to analyze, reliably, the state of 20 lakes last year.

“It’s like a big USB key. we bring it to the field, we prepare our water sample then we pass it in the machine on the ground and it takes three hours,” explains M^me Lord-Fontaine.

“The ministry does not have enough laboratory staff “a pea soup water”: quick to look in the microscope for several days on a large amount of lakes. ” she illustrates. This new technology would save time and labor costs. ”

Moreover. as our investigation office revealed yesterday, less lakes and rivers will be tested this year for water quality due to government budget cuts.

With new technology, the portrait of blue-green algae in Quebec will be more precise.

“We will have a better portrait of known lakes to have phenomena of efflorescence. but we will also be able to include lakes that we think is healthy,” adds Jérôme Comte.

“a pea soup water”: quick

He hopes to sample a hundred lakes this summer. The project will continue until September 2026.

For its part. the Ministry of the Environment, which collaborates in the project by providing samples, is cautious.

“It is an ambitious project. there are still many works to be carried out before the [ministère] Evaluates the possibility of using this new technology for the analysis of routine cyanobacteria, “said Josée Guimond, to the Communications Department of the Ministry of the Environment.