Cyanobacterial Blooms Study

Cyanobacterial Blooms Study in Canada

Cyanobacterial blooms are increasingly common in Canadian freshwater recreational water bodies, posing health risks to humans and animals due to toxin exposure. However, limited data exist on illness risks associated with recreational water contact at affected beaches. This study aims to fill this gap by investigating recreational water illness linked to cyanobacterial blooms at four popular beaches in Ontario, Manitoba, and Nova Scotia.

Study Activities and Results

2025 Study Continuation:
We are preparing to continue data collection in Windsor-Essex and Halifax in 2025. More information is coming soon!

2024 Study:
In 2024, surveys were administered at beaches in Manitoba (Grand Beach) and Ontario (Kinsmen) to gather data on water exposure and potential confounding factors. This was followed by 3 to 7 days of illness follow-up. Water samples were also collected to test for cyanobacteria counts, toxin strips, and chlorophyll. Preliminary findings from 1,481 participants show that 47.5% engaged in water activities, with 8.2% swallowing water. The overall AGI incidence was low (2.1%) but appeared to increase with water contact level, from 1.6% among those without contact to 2.6% for those who contacted water. Out of the 48 dog participants, the AGI incidence was 4.2%. The cyanobacterial counts on the study recruitment dates were low, except for a few day's extreme counts. These findings will further be explored with ongoing data collection in Windsor-Essex and Halifax in 2025.