Statistics Canada couldn't rely on Canadians accurately revealing their cannabis consumption so, they tested toilet water across the country.
Prior to legalization, Stats Canada was curious about cannabis consumption across the country. But, polling the public wouldn't suffice, thanks to the stigma surrounding cannabis.
So, they turned to THC-COOH levels in toilet water across Halifax, Montreal, Vancouver, Edmonton and Toronto to tell the truth.
THC-COOH "carboxy THC," lingers in urine long after cannabis is consumed. By looking at the concentration of THC-COOH in wastewater, Stats Canada can get a more accurate read on the total mass of cannabis consumed.
Cannabis Consumption By City
Of the five cities tested, Montreal had the most THC-COOH in their sewage system. Toronto came in second followed by Vancouver, Edmonton and Halifax.
The study, which was conducted from March to August 2018, found...
- Montréal has 1,922 grams/week, with an error interval of plus or minus 789 grams/week
- Toronto has 1,257 grams/week, with an error interval of plus or minus 651 grams/week
- Vancouver has 721 grams/week, with an error interval of plus or minus 200 grams/week
- Edmonton has 401 grams/week, with an error interval of plus or minus 137 grams/week
- Halifax has 265 grams/week, with an error interval of plus or minus 143 grams/week
Unsurprisingly, larger cities had higher levels of THC-COOH, partly because of the sheer size of their populations. This doesn't mean more people consume cannabis in Montreal, Toronto and Vancouver, a smaller pool of heavy consumers can easily skew the results.
If you expected Vancouver to have the highest consumption, you would be very wrong. Vancouver actually consumed the least per capita.
The city with the highest cannabis consumption per capita is actually the smallest. Halifax consumed the most per capita at approximately 1,310 micrograms/person-week.