Guest Blog by Morgan Murphy, Canada Summer Jobs Student and Conservation Biology student at Trent University
Have you ever intended on spending a warm summer day swimming in the lake, but something about the appearance of the water turned you off? Maybe the surface wasn’t as blue as it should be, but rather a questionable shade of green. Or maybe an unpleasant odour made it impossible to relax without a nose plug. This is the reality of tourists and locals of Innisfil and Georgina this week as public health officials confirmed the presence of toxic blue-green algae blooms in Lake Simcoe and Kempenfelt Bay. The affected areas include Innisfil Beach Park and Bear Point in Innisfil, and Roches Point Pier in Georgina.
What is Blue-Green Algae?
Blue-green algae is the common name for cyanobacteria. It is normal for low numbers of this bacteria to exist in lakes and streams, but a combination of increased temperatures, slow moving water, salt, and excess nutrients can spike the population size. When this happens, it’s called a bloom, and they can become toxic. Since it’s not possible to tell if a bloom is harmful from appearance, all blue-green algae outbreaks should be avoided. Blooms can be identified by green or turquoise water colour, scummy or paint-like appearance on the surface, a rotten smell, or dead animals along the shoreline.
Source: https://content.govdelivery.com/accounts/WIDHS/bulletins/2508e86
The reason it is so vital to identify these blooms as early as possible is because they can have impacts on human health. You can get sick by swimming in or drinking contaminated water and from eating contaminated fish or shellfish. Ingestion of cyanotoxins can cause stomach pain, headache, muscle weakness, dizziness, vomiting, diarrhea, and liver damage. Your skin, eyes, nose, throat, and lungs are also at risk of irritation, and a healthcare provider should be contacted if these symptoms occur after a swim.
It’s also important to remember that humans are not the only ones who can get sick from cyanotoxins. Dogs are at a particularly high risk as they are more likely to drink the water, eat dead animals found near a bloom, and lick scum or algae off themselves after a swim. Symptoms in animals include staggered walking, vomiting, respiratory distress, and even death. A veterinarian should be contacted immediately if any such symptoms occur after your pets have been in contact with water.
Algal Bloom Action in Ontario
Blue-green algae blooms in Ontario are currently handled by the Ministry of the Environment, Conservation and Parks. When a bloom is reported, local public health units and medical officers take samples to determine if the algae contains cyanotoxins. The unfortunate reality is that once a bloom has been confirmed, the ministry will not actually do anything to treat it. This is because algaecides can release toxins into the water, only creating further health issues in the lake. They rely on the blooms to disappear on their own, which can take a few days or a few weeks to occur. The only course of action currently required by the MECP is to issue health advisories and beach closures.
The issue with these untreatable blooms is that their appearance has become more frequent over time. Studies have shown that there has been an increase in reported cyanobacteria algal blooms in Ontario since 1994. This can in part be attributed to increasing global temperatures as a result of climate change. Warmer temperatures allow blue-green algae to grow faster and also prevents water mixing in the lake, further favouring the formation of thick algal mats.
Source: https://www.ontario.ca/page/water-quality-ontario-report-2012
Climate change is not the only culprit however, as cyanobacteria also requires nutrients like nitrogen and phosphorus for growth. Phosphorus pollution can come from easily identifiable point sources, or nonpoint sources that are harder to address. Specific point sources include sewage treatment plants and industrial sources like food processing and cleaning operations. Some non-point sources include animal waste, storm water runoff, shoreline erosion, and fertilizer.
At Lake Simcoe, urban stormwater runoff contributes to 31% of phosphorus loading. As urban sprawl and development continues in Ontario, this number is expected to increase. The Ministry of the Environment and Climate Change’s webpage says that everyone shares a responsibility in reducing phosphorus loading and suggests changes that each household should make. However, the most significant sources of phosphorus loading can only be controlled by regulations set in place by the government, such as stormwater treatment plans.
In 2009, the province committed to reducing phosphorus loads from an annual average of about 100 tonnes to 44 tonnes per year under the Lake Simcoe Protection Plan. Nonetheless, a comparison of the past two decades has shown that phosphorus loads are in fact rising, not falling, at Lake Simcoe. The average annual phosphorus load from 2000-2009 was 77.5 tonnes, whereas the average from 2010-2020 was 88 tonnes. It is concerning to see no improvement despite the province being given 15 years to provide results. Despite this lack of success, the province has yet to update the Phosphorus Reduction Strategy or create a plan to bring phosphorus loads down in any significant way.
Additionally, if it is built, the Bradford Bypass is expected to further contribute to the rise in blue-green algae in Lake Simcoe. Dust from construction sites is a known source of phosphorus that would end up in the waters of the wetlands being destroyed by the bypass. Another major source of pollution from the bypass would be road salt, which can cause lake stratification. This is when layers in the water stop mixing and certain contaminants can accumulate. Studies have shown that the addition of NaCl to rivers can release significant amounts of nitrogen and phosphorus, both of which feed blue-green algae growth.
Take Action
The government wants us all to play a part in reducing phosphorus in Lake Simcoe, but we must first remind them of their responsibility to provide us with a transparent and honest commitment to our environment. If you care about the health and safety of Lake Simcoe, the Rescue Lake Simcoe Coalition encourages you to urge the province to provide swift and appropriate planning to prevent toxic algal blooms. Click here to send a message to the Ontario government inquiring about their plan to reduce phosphorus loading under the Lake Simcoe Protection Plan. Click here to sign a petition to support using a salt alternative on the Bradford Bypass.
If you believe you’ve found a blue-green algae bloom, contact the Ministry of the Environment, Conservation and Parks. You can report your concerns online or by phone.
Sources:
https://www.ontario.ca/page/lake-simcoe-phosphorus-reduction-strategy
https://www.sciencedirect.com/science/article/pii/S0048969722044345
https://www.ontario.ca/page/blue-green-algae
https://www.ontario.ca/page/lake-simcoe-phosphorus-reduction-strategy
https://www.ontario.ca/page/lake-simcoe-protection-plan
https://onlinelibrary.wiley.com/doi/10.1002/9781119068761.ch1
https://www.ontario.ca/page/ministers-annual-report-drinking-water-2023
https://wodnesprawy.pl/en/water-salinity-promotes-eutrophication-of-surface-waters/
https://lakesimcoewatch.ca/wp-content/uploads/2024/03/Phosphorus-Loads-2000-2020.pdf