Risks to People and Pets
While many forms of blue-green algae are harmless, some may produce toxins. If you see HABs in a waterway, do not swim, drink or use the water. Keep animals away from the water too. Longer exposure to more severe toxins in the water through drinking, swimming, bathing, cooking or washing may lead to health problems. This includes: itchy, irritated eyes and skin; headache; fever; diarrhea; abdominal pain; nausea; and vomiting.
NOTE: Never boil the water, as it kills the algae resulting in the release of more toxins. If you feel unwell after encountering a HAB, seek medical attention.
What to do if you see Harmful Algae Blooms in the water?
If you live or use a lake or waterway, be on the lookout for HABs. If you spot a bloom, report it to the Spills Action Centre at 1-800-268-6060. If your home or cottage gets its drinking water from a local waterway, consider using test strips (for example, Algal Toxin Test Strip Kits - eurofins-technologies.com) to check if algae toxins are present, even if a bloom is not visible. In general, HABs can be placed in one of three categories depending on how bad they are. In categories 2 or 3, people should not swim or use water at all. Use this chart to identify the category and actions to take to stay safe.
Protecting Your Drinking Water
If you get drinking water from a lake, river, creek, or a shallow well near a body of water, ensure the water is properly treated to protect against harmful bacteria and HABs. Water treatment is a complex process. Consult a qualified professional who can assess your water supply to ensure the best treatment system is in place. If unsure about the effectiveness of your water treatment system, find another source of drinking water such as a drilled well, a dug well far from shore, or water holding tank filled with water from a licensed water treatment plant. An alternate water source may also be recommended if you draw water from a water source that has frequent HABs.
Human activities (like fertilizer runoff, agricultural runoff and faulty septic systems) can increase levels of phosphorus and nitrogen in the water. This can lead to the growth of HABs. To reduce the nutrient levels in water that promote algae growth, do the following:
- Use phosphate-free laundry detergents.
- Avoid using fertilizers.
- Reduce surface runoff by maintaining a naturalized shoreline on waterfront properties.
- Ensure septic systems work properly and are maintained so sewage does not leak.