Article by Lakshimi Sadu, Globe and Mail
Statistics Canada is using a unique way of tracking the black market in cannabis since legalization: analyzing the sewage of five cities to determine how much pot residents are consuming.
The results suggest that between March and August Halifax had the highest rate of consumption per capita, at 1,310 micrograms per week, with Montreal coming in second at 976. Toronto came in at 451, Edmonton at 416 and Vancouver at 288. The areas surveyed represent almost 8.4 million Canadians.
They are trace amounts – a microgram is a millionth of a gram. But Anthony Peluso, one of the researchers of the waste-water project and the assistant director at Statistics Canada, said the goal was to track consumption data consistently.
“There may be some flaws in it, but I think if the flaws are consistent over time, then the trend will emerge,” he said.
When people smoke cannabis, the active ingredient THC is excreted from the body and flushed into the municipal waste water system. Statscan then analyzes this sewage water to determine the cannabis consumption levels in the city.