"Something must have happened 30 years ago because there was a culture of swimming in Lake Ontario, in Toronto. They had lake races — there's lots of evidence that people used the water and went right into the lake," she said.
She's not wrong. Here's a look at what some Toronto beaches in the summer used to look like.
So why not swim now?
Despite the fact that the city tracks E. coli levels and the city's beaches get international Blue Flag awards if they meet certain water quality standards, fear of pollution seems to deter people from getting their feet wet.
This concern, McDonnell says, is something that didn't hinder beach-goers in past decades as much as it does now.
If it's not the pollution that keeps people from entering the lake, it might be the temperatures.