In March 2018, Statistics Canada launched the largest "wastewater-based epidemiology pilot test" ever conducted in North America. Over a 12 month period, it collected wastewater samples across the country in order to test for traces of cannabis and other drugs. The pilot captured 8.4 million people in Vancouver, Edmonton, Toronto, Montréal, and Halifax. And it was allegedly timed to coincide with the legalization of cannabis in Canada on October 17, 2018.

This week Statistics Canada published its findings. While the study does cover over 8 million people, it was not intended to be representative of the entire Canadian population. Some sites, such as Vancouver, had nearly complete coverage of the metro area population. While others, such as the Halifax site, only covered about half of the metropolitan area. In any event, the findings are interesting.

Above is one example: methamphetamine load per capita for the five study cities. The y-axis is grams per million people per week. And the time period is, again, March 2018 to February 2019. Average levels for Edmonton and Vancouver were found to be about 3.7x higher than those in Montréal and Toronto. There was also no apparent seasonal/monthly variation, which is something else they looked at.

Here I learned that a large portion of this drug passes through the body unchanged. And so the concentrations they discovered in wastewater is likely a fairly direct indicator of consumption within the population. Stats Canada is still reviewing its findings and evaluating this approach to collecting large scale urban data. But I am certain we'll be seeing more of these kinds of urban studies.

Chart: Statistics Canada