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

LETTER: I’m sorry, Surrey, for smelling like cigarettes all those years

If I could go back and tell my 13-year-old self to put down that cigarette, I would, reader says

‘A bag full of garbage every 15 metres’: Surrey industrial area filled with trash

Local workers looking to recruit business, raise funds to help dispose of litter

Survey suggests 83 per cent of Surreyites ‘favour a referendum’ on policing transition

Survey was conducted by Pollara Strategic Insights on behalf of the National Police Federation

Racist graffiti sparks Cloverdale man to renew calls for City to clean up street

Hate message the latest garbage dumped at the end of 176th Street

VIDEO: Behind the scenes of turning newspapers into digital archives

Kelowna Capital News donated materials dating from 1980 to 2000

Landlord ordered to pay $11K after harassing B.C. mom to move days after giving birth

Germaine Valdez was pressured to move just a few days after giving birth by C-section to her child

Heart attacks strike B.C. husband and wife just over one year apart

Courtenay couple share personal stories to bring awareness to heart month

‘Nothing surprises us anymore:’ U.S. border officials find brain in package

U.S. Customs and Border Protection agents found the brain packed in a glass mason jar in a Canada Post shipment

VIDEO: Giants winning streak now stands at 11

Team erased a 5-2 deficit by scoring every five minutes

Fiery collision involving truck closes Highway 1 at Three Valley Gap

Drivers should expect major delays and congestion; estimated time of re-opening is 2 p.m.

B.C., Ottawa sign sweeping 30-year deal for northern caribou habitat

West Moberly, Saulteau co-manage new protection on two million acres

Eyes on police after Trudeau orders blockades torn down, injunctions enforced

The RCMP in B.C. have sent a letter to the traditional leaders of the Wet’suwet’en Nation

B.C. massage therapist suspended following allegations of sexual misconduct

While suspended, Leonard Krekic is not entitled to practice as an RMT in B.C.

Most Read