Blue-Green Algae Bloom
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In the past few years, blue-green algae blooms have formed off the southwest region of Lake Erie near Pelee Island. During a bloom wind conditions may move the blue-green algae bloom towards the shores of Windsor-Essex County and Pelee Island, which could contaminate some sources of drinking water and beaches.
Residents and visitors are urged to take a cautious approach, monitor the situation, and protect themselves from potential health risks.
What are blue-green algae?
Blue-green algae (Cyanobacteria) are microscopic bacteria that occur naturally in fresh water lakes, ponds, rivers and streams in the late summer and early fall. In warm weather, with the right nutrients (phosphorous and nitrogen) and low wind, they can form a large mass called a bloom. These blooms can make the water appear bluish-green, can form solid looking clumps, and may contain toxins that can be dangerous to your health and the health of your animals.
The most common toxins produced in a bloom are called microcystins.
Those most at risk are children 6 years of age and younger.
How can you be exposed?
- Direct skin contact (swimming).
- Swallowing (drinking water).
- Eating fish caught in water where blue-green algae blooms occur.
- Inhaling mist in the air containing blue green algae cells or toxins (e.g., waterskiing, showering).
What are the Health Effects?
Contact with microcystins can produce the following negative health effects:
- Itchy, irritated eyes and skin if you swim, bathe, or shower in contaminated water.
- Small quantities - headaches, fever, diarrhea, abdominal pain, nausea, and vomiting.
- Large quantities - more serious health effects may occur such as liver damage.
Contact your health care provider if you have any of the above symptoms.
What’s being done to monitor for blue-green algae?
Organizations such as your Municipality, the Windsor-Essex County Health Unit, the Essex-Region Conservation Authority, the Ministry of Environment and Climate Change, etc., work together to monitor and test the water in the following ways:
- Visually monitor area lakes and waterways.
- Test the municipal drinking water systems.
- Monitor satellite images.
- Report results to the Health Unit.
- Issue advisories and warnings to the public as needed.
Level of Microcystins - Parts per Billion (ppb)
1.5 ppb to 10 ppb
10 ppb or higher
(20 ppb or higher as per Health Canada, 2012)
Please note that infants and young children (under age 6) are most at risk of developing health problems (e.g., liver damage) from exposure to blue-green algae. During a blue-green algae bloom, the following precautions are recommended:
- Do not drink water drawn from the affected water source.
- Ensure boiled bottled water is used for all infant feeding preparation.
- Do not swim or play in affected water.
Drinking Water Recommendations:
Level of Microcystins - Parts per Billion (ppb)
Recommendations if using a Well/ Cistern that draws water from Lake Erie (e.g., private cottages with a well)
Recommendations if using Municipal Drinking Water
Greater than 0.3 ppb
(United States Environmental Protection Agency, 2015)
Greater than 1.5 ppb
(Ontario Drinking Water Quality Standard)
For ALL families, pets and livestock animals:
Acceptable levels of Microcystins
- Less than 20 ppb for recreational water quality.
World Health Organization (2003) and Health Canada (2012)
- Less than 10 ppb for safe recreational water quality.
Windsor-Essex County Health Unit
- Less than 1.5 ppb for drinking water quality.
Ontario Drinking Water Quality Standard
- Less than 0.3 ppb for drinking water quality for infants and young children under age 6.
United States Environmental Protection Agency (2015)
Protect your pets and livestock
Avoid letting pets and livestock animals drink or swim in water during a bloom as they may suffer serious health risks including death. If they have come in contact with the water, rinse them off right away with clean water.
DO NOT BOIL THE WATER DURING A BLUE-GREEN ALGAE BLOOM!
Do not boil your water or manually treat the water with chlorine or other disinfectants. Boiling or treating the water makes it more toxic because it opens the cells and releases the bacteria’s toxin. A Boil Water Advisory (BWA) is never issued during a blue-green algae bloom; an alternate water source must be used.
Use caution when considering eating fish caught in water affected by a major blue- green algae bloom. Eating these fish might make you sick. It is recommended to avoid eating fish from waters during a blue- green algae bloom and for two weeks after the bloom. Refer to the Guide to Eating Ontario Fish 2017-2018 for more information.
What if I suspect a blue-green algae bloom?
- Assume it is toxic
- DO NOT swim, drink, or bathe in the water
- Restrict pets and livestock from using the water
- Call the Ministry of the Environment and Climate Change’s Spills Action Centre at 1-800-268-6060
- Call WECHU to report it and for more information at 519-258-2146 ext. 4475
How can I help prevent the growth of blue-green algae?
- Use phosphate- free soaps, detergents and cleaning products.
- Avoid using lawn fertilizers, especially those that contain phosphorous.
- Ensure your septic tank is in good working condition and not leaking into the water.
- Maintain a natural shoreline on waterfront properties.
Plant and maintain vegetation along waterways to reduce agricultural runoff.
How Do I Prepare An Emergency Water Supply?
- Store at least a 3 day supply of water for your household (try to store a 2 week supply if possible).
- On average each person and pet uses at least 2 litres of water per day. You should consider storing more water for summer weather, for pregnant women, and for persons who are ill.
- Check the expiration date of store-bought water and replace stored water every 6 months.
What types of containers can I use for water storage?
A supply of unopened commercially bottled water is the safest and most reliable emergency water supply.
If you’re preparing stored water yourself, you should use food-grade water storage containers, such as those found at surplus or camping supply stores.
- Do not use containers that have been used for any toxic solid or liquid chemicals (e.g., old bleach containers).
- Do not use containers that cannot be sealed tightly.
- Do not use containers that can break, such as glass bottles.
- Do not use plastic or cardboard bottles, jugs, and containers used for milk or fruit juices.
How should I clean my storage containers?
Before filling with safe water, use these steps to clean and sanitize storage containers:
- Wash the storage container with dishwashing soap and water and rinse completely with clean water.
- Sanitize the container by adding a solution made by mixing 1 teaspoon of unscented liquid household chlorine bleach in 1 litre of water.
- Cover the container and shake it well so that the sanitizing bleach solution touches all inside surfaces of the container.
- Wait at least 30 seconds and then pour the sanitizing solution out of the container.
- Let the empty sanitized container air-dry before use OR rinse the empty container with clean, safe water that already is available.
For more information
You can speak to a Public Health Inspector at 519-258-2146 ext. 4475.
Centers for Disease Control and Prevention. (2013). Personal preparation and storage of safe water. Retrieved from http://www.cdc.gov/healthywater/emergency/safe_water/personal.html
Health Canada. (2008). Guidelines for Canadian drinking water quality: Guideline technical document – cyanobacterial toxins - Microcystin-LR.
Health Canada. (2012). Guidelines for Canadian recreational water quality, 3rd edition. Retrieved from http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/guide_water-2012-guide_eau/index-eng.php#a6
Ontario Ministry of the Environment and Climate Change (2016). Blue-green algae. Retrieved from http://www.ontario.ca/environment-and-energy/blue-green-algae
Ontario Ministry of the Environment and Climate Change. (2017). Guide to eating Ontario fish, 29th edition. Retrieved from https://www.ontario.ca/document/guide-eating-ontario-fish
Ontario Ministry of the Environment and Climate Change. (2014). Information about blue- green algae: Background, potential impacts to human health and safety of drinking water. Toronto: Queen's Printer for Ontario.
United States Environmental Protection Agency. (2015). Recommendations for public waters systems to manage cyanotoxins in drinking water.
World Health Organization. (2020). Cyanobacterial toxins: Microcystins. Background document for development of WHO Guidelines for drinking-water quality and Guidelines for safe recreational water environments.