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.

Just Posted

Fire ban back in effect for Northwest Fire Centre region

Starting May 24, both Category 2 and Category 3 prohibitions will be in place

Kelowna company wins contract for LNG Canada project in Kitimat

SK Form & Finish will work with equivalent of 4,000 fully loaded concrete trucks

U.S. tariffs on Canadian aluminium scrapped

Joint effort by industry, government and unions secures deal

Rio Tinto BC Works watching Nechako reservoir levels closely

Dropping water levels could threaten power generation operations

VIDEO: Canadian breaks women’s world record for longest plank

Dana Glowacka, of Montreal, held a plank for four hours and 20 minutes

Kamloops girl, 9, recovering from carbon monoxide poisoning now out of ICU

Her mother who was sleeping in the same tent with her did not survive

‘I think he’s still alive’: B.C. mom pleads for help finding son last seen a month ago

Family offering $5,000 reward for information leading to the safe return of Tim Delahaye

New poll suggests one-third don’t want politicians to wear religious symbols

Local politicians shouldn’t be allowed to wear hijabs, crucifixes or turbans on the job, survey suggests

Raptors fans far from home adjust plans to watch pivotal playoff game

Raptors currently lead the playoff series 3-2, and a win Saturday would vault them into NBA finals

PHOTOS: First responders in Fernie rescue baby owl who fell from nest

The baby owl’s inability to fly back to its nest prompted a rescue by first responders

Five takeaways from the Court of Appeal ruling on B.C.’s pipeline law

It’s unclear how many tools are left in B.C.’s toolbox to fight the project

B.C. port workers set to strike on Monday in Vancouver

A strike at two container terminals would affect Canadian trade to Asia

Scheer says it would take Conservatives five years to balance budget

Scheeraccused the Liberal government of spending $79.5 billion of previously unbudgeted funds

Most Read