Cannabis plants in BlissCo, a manufacturing facility in Langley, B.C. (Ashley Wadhwani/Black Press Media)

Here’s a first look at Canada’s sewage tests for cannabis use

The first-of-its-kind tests involve gauging traces of THC, the active ingredient in marijuana, at 15 wastewater treatment plants in Canada

Canadians eat or smoke anywhere between 400 to 1,600 tonnes of cannabis per year, according to a few months of sewage samples examined for the federal government.

The wide-ranging estimate, released by Statistics Canada on Thursday, is the first look at cannabis use through a new technique called wastewater-based epidemiology. The tests involve gauging traces of THC, the active ingredient in marijuana, at 15 wastewater treatment plants in five different cities, including Vancouver.

After cannabis is metabolized in the body, traces of THC are left behind in human waste. Scientists collected wastewater on the second week of each month from March to August this year – before cannabis was legalized in Canada on Oct. 17.

As expected, more cannabis is consumed in Canada’s larger cities. Montreal had the highest rate of consumption at roughly 1,922 grams per week, according to the analysis. Toronto had the second highest at 1,257 grams, followed by Vancouver with 721 grams.

READ MORE: Canadian trial to compare cannabis and fentanyl in relieving chronic pain

READ MORE: B.C. woman looks to reduce stigma surrounding weed-smoking moms

The sample tests were meant to overcome under-reporting by cannabis users, often caused by the stigma of the drug and reluctance for people to admit their illegal purchases.

“One consequence of under-reporting is that the size of the black market for cannabis will be similarly underestimated,” the report reads.

“As a result, without a direct measurement of cannabis consumption, the reduction of the black market for cannabis – one of the objectives of the legalization of non-medical cannabis – will be hard to track.”

READ MORE: 10 things still illegal in the new age of recreational cannabis

While the estimates offer a first look at the truth behind cannabis use, Statistics Canada said the numbers are experimental and that more information is needed, such as how much of the drug is excreted, its potency and the way the drug is consumed. Other factors to consider include different chemicals in the various treatment plants themselves.

“In the case of cannabis, there are many different kinds of products, with different THC potency levels, and this adds further complexity to estimation methods,” the report reads.

Sampling will continue until the spring of 2019.

WATCH: Inside a B.C.-based marijuana production facility


@ashwadhwani
ashley.wadhwani@bpdigital.ca

Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Maple Ridge woman fights WorkSafe B.C. over police widow’s pension

Dalila Vroom says husband, Const. Robert Vroom, died as result of PTSD from time with Abbotsford PD

Abbotsford Hospital COVID-19 outbreak over, a new one reported at business

New World Technologies is site of ‘very small’ outbreak, says Dr. Bonnie Henry

UPDATED: Missing Abbotsford man, 77, found safe and sound

John Brooks had last been seen getting on a bus on Monday, June 1

Solidarity demonstration planned for Abbotsford on Friday

People gathering to protest police brutality and systemic racism in downtown Abbotsford

New rules set stage for more patios in Abbotsford during COVID-19

City eases rules for restaurants hoping to expand their footprint outside during pandemic

B.C. records four new COVID-19 cases, Abbotsford hospital outbreak cleared

Four senior home outbreaks also declared over, eight still active

Facing changes together: Your community, your journalists

New platform allows readers to make a one-time or ongoing donation to support local journalism

RCMP, coroner investigate murder-suicide on Salt Spring Island

Two dead, police say there is no risk to the public

About 30% of B.C. students return to schools as in-class teaching restarts amid pandemic

Education minister noted that in-class instruction remains optional

Trudeau avoids questions about anti-racism protesters dispersed for Trump photo-op

Prime minister says racism is an issue Canadians must tackle at home, too

B.C.’s Law Enforcement Torch Run for Special Olympics goes virtual

The annual event partnering RCMP with Special Olympians is dramatically altered by COVID-19

Bateman program encourages people to sketch outside, connect with nature

#MyNatureSketch initiative encourages Canadians to become ‘bright-eyed three year olds’

Be cautious expanding COVID-19 bubble, Dr. Bonnie Henry tells B.C.

Senior homes stay off-limits as schools, businesses reopen

Most Read