Trace amounts found in water coming from 15 plants in Ontario

Painkillers and other drugs that are flushed down toilets will inevitably pour out of household taps in trace amounts around the world, a University of Toronto drinking water expert says.

Civil engineer Ron Hofmann, who specializes in drinking water toxins, says that a recent report finding painkillers, antibiotics and cholesterol lowering drugs in the water coming from 15 Southern Ontario treatment plants was "not surprising at all" to people in the field.


"It’s been known for many years that these things could be in the tap water," says Hofmann.

Hofmann says the drugs enter the water supply when people emit small amounts of unmetabolized medications through their urine, or throw unused pills down the sink or toilet.

"They make their way through to the wastewater treatment plants and out into the environment," he says. "And once they’re there, they eventually will make it into the tap water."

The Ontario study was conducted out of Environment Canada’s National Water Research Institute in Burlington.

The study, which appeared in the Water Quality Research Journal of Canada, says the drugs were detected in extremely low concentrations, a finding Hofmann also said would be expected.

U of T civil engineering professor Robert Andrews says there is some debate about the potential health effects of the tap water drugs.

"That’s the million dollar question," says Andrews. "Right now there is nothing that’s really indicting (any danger) because the concentrations are so small compared to what you would take for medicinal purposes."

in Toronto

  • Lake Ontario, the source of Toronto’s drinking water, would almost certainly contain trace amounts of drugs, experts say.