Quebec is dotted with lakes and other bodies of water. Not only do they offer breathtaking scenery, but they also play a vital role in the ecological and economic balance of many regions. In recent years, the state of Quebec's lakes has become increasingly worrying. What is happening to the health of these precious ecosystems and the preservation of our water?
1. The situation in numbers
Today, over 800 lakes are active Réseau de surveillance volontaire des lacs (RSVL) members. However, the information currently available concerns 765 lakes. A total of 204 bodies of water are considered to be of concern. Of these, 10 are considered hyper-eutrophic (worst stage) and 19 eutrophic (second worst stage).
The rating mentioned above scale has seven stages:
- ultra-oligotrophic
- oligotrophic
- oligo-mesotrophic
- mesotrophic
- meso-eutrophic
- eutrophic
- hyper-eutrophic
1.1. Where do these figures come from?
These figures come from the Réseau de surveillance volontaire des lacs (voluntary lake monitoring network). This is a program of the Ministère de l'Environnement that actively engages lakeshore residents in acquiring knowledge about water quality.
The data collected provides a better understanding of the dynamics and changing state of Quebec's lakes. They play an essential role for the various watershed organizations and for those seeking solutions to preserve these bodies of water.
It is important to note, however, that lake quality monitoring is still based on a fragile foundation. It depends largely on the work of volunteers. Additionally, only a small fraction of Quebec's 3.6 million freshwater bodies are subject to analysis, and around 35% of registered lakes are in the Laurentians.
2. Threats to Quebec's lakes
Quebec's lakes face a complex array of threats that jeopardize their fragile natural balance. These threats are vast and varied. Here is an overview.
2.1. Eutrophication
Eutrophication is the phenomenon whereby nutrients accumulate in an environment. It is a natural phenomenon that takes place over thousands of years, and becomes problematic when it occurs too rapidly. It is therefore important to distinguish between natural eutrophication, which takes place over thousands of years, and anthropogenic eutrophication, which takes place over a few decades.
The problem of anthropogenic (i.e. man-made) eutrophication occurs when excessive quantities of nutrients, such as nitrogen and phosphorus, are introduced into a lake in large quantities and very quickly. Typically, this is due to human activities such as agriculture, deforestation, the use of septic tanks and lawn fertilizers.
Eutrophication causes an extreme proliferation of aquatic plants, particularly algae, which consume the oxygen dissolved in the water. This can lead to the death of fish, plants and other aquatic organisms, seriously disrupting the lake's ecosystem. Richard Carignan, a professor at the Université de Montréal, has extensively studied the accelerated eutrophication of lakes. According to him, about 10% of Quebec's inhabited lakes are affected.
2.2 Cyanobacteria
Cyanobacteria, also known as blue-green algae, represent another serious threat to Quebec lakes. They are particularly active when there is an excess of nutrients, i.e. when a lake is eutrophic or hyper-eutrophic.
When these micro-organisms proliferate too rapidly and reach high levels, they can produce toxins that are potentially dangerous to human and animal health. Swimming and other aquatic activities can no longer be practiced in these bodies of water.
The number of reports of cyanobacteria made to the Ministère de l'Environnement by citizens rose from 61 to 265 between 2019 and 2021. That's a leap of 334% in just two years. These reports testify to the growing prevalence of blue-green algae in Quebec lakes and the need for measures to control them.
2.3 Wastewater
Wastewater is another factor in the deterioration of Quebec's lakes. Aging and inadequate wastewater management infrastructures can lead to untreated discharges of fecal matter and chemicals into lakes, contributing to water pollution.
Many experts are calling for investment in repairing and optimizing these infrastructures to reduce drinking water losses and untreated wastewater discharges into ecosystems. According to a study commissioned by Réseau Environnement, such a reduction would generate $324 million in profits and limit the deterioration of the environment and water throughout Quebec.
This is not just a municipal responsibility. Homeowners with septic systems on their property have a duty to maintain them and ensure they comply with environmental standards. That's one of the reasons why eco-responsible wastewater treatment systems like Ecoflo are becoming increasingly popular.
3. Consequences of the deterioration of Quebec's lakes
The state of Quebec's lakes has a major impact on the quality of life of many species, including humans.
3.1 Impact on biodiversity
When the state of lakes deteriorates due to eutrophication, cyanobacteria and other factors, aquatic biodiversity is jeopardized. The species of fish, invertebrates and aquatic plants that inhabit these ecosystems suffer from the lack of oxygen or the presence of toxins produced by cyanobacteria.
3.2. Impact on local communities
The quality of life of local communities is closely linked to the health of lakes. Local populations are affected in various ways. The state of lakes can make swimming and fishing less pleasant, if not impossible. Cyanobacteria can produce toxins that irritate the skin, eyes and throat. If ingested, contaminated water can cause stomach pains, fever, diarrhea and vomiting.
3.3 Economic impact
In addition to the environmental and social consequences, lake deterioration also has a significant economic impact. The collapse of lake-related industries such as fishing and tourism can mean the loss of jobs and income for many people.
The attractiveness of lakeside properties is also affected. Some homeowners have seen the value of their property drop by as much as 25% due to the poor health of their neighbouring lake.
Learn more about the consequences of water pollution.
Taking action to improve the state of Quebec's lakes
All levels of government have a role to play in protecting lakes and water. This means investing in monitoring, infrastructure rehabilitation and watershed protection policies. This is what the Canadian Coalition for Healthy Waters is calling for. Protecting these precious ecosystems is a shared responsibility. There are many ways in which each of us can contribute to water preservation.
"The lakes of Quebec and Canada are a priceless natural treasure that deserves to be protected for future generations. It's time to act collectively to ensure the health and sustainability of these vital ecosystems." - Nan-B de Gaspé Beaubien