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

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

Toronto Public Health nurse Lalaine Agarin makes preparations at Toronto’s mass vaccination clinic, Jan. 17, 2021. THE CANADIAN PRESS/Frank Gunn
3 deaths, 234 new cases of COVID-19 in Interior Health over the weekend

One death connected to outbreak at Kamloops’ Royal Inland Hospital, where 20 patients and 28 staff have tested positive

(THE NEWS – files)
Snowy days ahead for the Okanagan and Shuswap

The region could get up to 5 cm by Thursday

Penticton Search and Rescue completed two rescues in succession of each other Saturday, Jan. 23, 2021 afternoon. (PENSAR / Facebook)
Penticton Search and Rescue members execute back-to-back rescues

PENSAR had barely completed their first rescue of the day when they received a second call

People skate on a lake in a city park in Montreal, Sunday, January 10, 2021. THE CANADIAN PRESS/Graham Hughes
The end of hugs: How COVID-19 has changed daily life a year after Canada’s 1st case

Today marks the one year anniversary of COVID-19 landing in Canada

Crystal Johns used her lunch break to film her audition video for the Vancouver Canucks.
VIDEO: Former Vees anthem singer wants to bring her voice to the Canucks

Crystal Johns made her audition tape during a lunch break

Crews with Discovery Channel film as an Aggressive Towing driver moves a Grumman S2F Tracker aircraft around a 90-degree turn from its compound and onto the road on Saturday, Jan. 23, 2021. It was the “most difficult” part of the move for the airplane, one organizer said. (Jenna Hauck/ Chilliwack Progress)
VIDEO: Vintage military plane gets towed from Chilliwack to Greater Victoria

Grumman CP-121 Tracker’s eventual home the British Columbia Aviation Museum on Vancouver Island

Heather Barker. (File)
Manslaughter charge laid in Vernon woman’s 2018 death

Shaun Ross Wiebe, 43, faces manslaughter and assault charges related to the death of Heather Barker

Zaudanawng “Jay-Dan” Maran in his Creston home. Hanging on the wall behind him is a logo of Kachin’s Manaw festival. Photo: Aaron Hemens
From Myanmar to Creston: The story of a refugee

In October 2007, Zaudanawng “Jay-Dan” Maran and his friends encountered a woman being sexually assaulted by two Myanmar soldiers.

Protesting farmers and their families gather around a bonfire to mark the harvest festival, which is called Lohri, on a blocked highway in protest against new farm laws on the outskirts of New Delhi, India, Wednesday, Jan. 13, 2021. Changes in India’s farm laws could potentially open up one of the world’s most populous markets and are being closely watched by Canada’s agricultural and economic sectors, say experts. THE CANADIAN PRESS/AP-Altaf Qadri
UBCO students asking for support in raising funds for Indian farmers

UBCO’s Bhangra Club and Punjabi Student Association are raising funds for Khalsa Aid

Kamloops This Week.
48 COVID-19 cases and one death associated with outbreak at Kamloops hospital

One of the 20 patients infected has died, meanwhile 28 staff with COVID-19 are isolating at home

The City of Vernon is sending a letter to the provincial government to request that church be deemed an essential service amid the pandemic. (Brendan Shykora - Morning Star)
Vernon mayor scolded for revealing stance on making church essential

Coun. Scott Anderson calls Cummings’ actions ‘arrogant’

The scene of a serious crash on Highway 33 in Kelowna that killed one and severely injured two others on June 20, 2018. (File)
Driver found guilty of causing death, injury in 2018 Kelowna crash

Travis Ryan Hennessy will face sentencing at a later date

(Michael Rodriguez - Capital News staff)
Downtown stairwell fire suspicious, Kelowna RCMP say

Crews were called to Gotham Nightclub for a report of a stairwell fire

Rolling seven-day average of cases by B.C. health authority to Jan. 21. Fraser Health in purple, Vancouver Coastal red, Interior Health orange, Northern Health green and Vancouver Island blue. (B.C. Centre for Disease Control)
2nd COVID vaccine doses on hold as B.C. delivery delayed again

New COVID-19 cases slowing in Fraser Health region

Most Read