Some Ontario beaches have been deemed unsafe for swimming by public health authorities as a heat warning remains in effect for southern parts of the province.
Toronto Public Health is advising caution at the popular Centre Island beach on the Toronto Islands, after water samples showed elevated E.coli bacteria counts.
Meanwhile in Ottawa, E.coli counts at Mooney's Bay Beach and Petrie East Bay are above the provincial threshold, according to data collected last week.
Ottawa Public Health transitioned this year to testing waters once a week, whereas Toronto Public Health continues to sample water from beaches on a daily basis.
A researcher at Ottawa's Carleton University is currently testing the waters at five locations along the Rideau River to address knowledge gaps in water testing and safety.
The research suggests the river water is often cleaner than people think, and safer than many lakes.
This report by The Canadian Press was first published July 29, 2025.
The Canadian Press
