By Menaka Wilhelm
As a bill that would legalize recreational marijuana works its way through the Canadian Parliament, the government is gearing up to track cannabis consumption more closely than it has before. Statistics Canada has begun to do city-scale drug screening by monitoring what Canadians flush down the toilet.
Six cities have agreed to contribute samples from the place where all drains congregate — their wastewater treatment plants. Toronto, Montreal, Edmonton, Alberta; Vancouver and Surrey in British Columbia; and Halifax, Nova Scotia, will participate. All told, the network would capture data on drug use from about a quarter of Canada’s total 36 million inhabitants.
Prime Minister Justin Trudeau had aimed to legalize marijuana by July, but the draft legislation still has a ways to go. After the Canadian Senate passed it on March 22, five committees are now considering changes.
Regardless of what happens with marijuana legislation in Ottawa, Statistics Canada has already begun testing sewage for signs of drugs. Canada joins several countries in Europe that sample wastewater for drugs annually. New Zealand has been collecting data from sewage since last year, and Australia tests nearly half of its population’s wastewater for substance use.