What we can learn about winter water quality

In anticipation of all the exciting work in store for Ontario Place, we’ve begun sampling the waters there, and will continue year-round.

Ontario Place’s West Island Beach is a natural oasis amidst bustling city life, and is an already beloved destination for swimming and other water recreational activities (yes, even in the winter!).

This beach has tons of potential to become the newest swimmable urban spot on Lake Ontario, as more and more Torontonians and visitors are discovering the hidden gem.

That’s why our initial water quality results from sampling on January 27th are so worrisome. 

In Toronto, a beach is considered unsafe for recreation when the geometric mean of 5 samples collected within a given swimming area exceeds 100 counts of E. coli in 100 milliliters of water. Our samples at Ontario Place revealed E. coli counts ranging from 1,011 to just over 3,465—that’s about 22 times more than what is considered a safe amount.

This is an extremely high level of E. coli contamination for this particular spot. For comparison, the highest result from sampling over the summer was 1,299.7 E. coli / 100 mL. This huge failure happened after a heavy rainfall. 

So, to put it in layman’s terms — it’s not good water quality and quite unusual for this time of year.

Although it’s impossible to say definitively what caused the failure, our Great Lakes Community Monitoring Coordinator in Toronto, Isabel Fleisher, had a few educated guesses. She surmises that the failure on January 27th may have happened due to high winds and high wave action, which could have disrupted the bottom sediment in which E. coli tends to live longer life than water. Another possible cause of the failure could have been southwest winds bringing E. coli into the beach from a western combined sewer overflow pipe, perhaps in the Humber area. What makes the failure especially surprising is that E. coli tends to thrive in warm water.

Since sampling began at Ontario Place West Island Beach in 2019, the average water quality has fluctuated quite a bit. This highlights the importance of monitoring the water at Ontario Place, and continuing to learn about the trends that can affect the health of those swimming there.

Stay tuned for more updates on Ontario Place water quality, and check the Ontario Place West Island Beach Swim Guide page for the latest water quality results.