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

Port Alberni will have a salmon derby on Labour Day after all

Alberni Valley Tyee Club reveals ‘socially distanced’ derby only for Labour Day 2020

NIC practical nursing students hone skills on pandemic’s front line

‘It also has become clear that this is my thing,’ – NIC practical nursing student Breanna Patterson

Fisherman snags barracuda off Vancouver Island in rare encounter

Ferocious fish, not native to Canada, was netted and released in Alberni Inlet

Vancouver Island family loses everything after house fire next door

Friends of Paula and Clifford Lucas are raising funds to help the young family

North Island College announces 2020 graduation award winners

North Island College has announced the award recipients for the 2020 Graduation… Continue reading

B.C. records 62 new COVID-19 cases, two deaths since Friday

Province has just over 200 active cases

Hotel rooms for B.C. homeless too hasty, NDP government told

Businesses forced out, but crime goes down, minister says

Suspicious fire quenched before reaching gunpowder in Nanaimo’s historic Bastion

Probe underway in basement blaze that erupted near where powder stored to fire signature cannons

Duncan model makes quarter finals in ‘Maxim’ magazine contest

Brandee Peart among top one per cent left in competition

Wage subsidy will be extended until December amid post-COVID reopening: Trudeau

Trudeau said the extension will ‘give greater certainty and support to businesses’

B.C. government prepares for COVID-19 economic recovery efforts

New measures after July consultation, Carole James says

Tree planters get help with COVID-19 protective measures

Ottawa funds extra transportation, sanitizing for crews

Trudeau apologizes for not recusing himself from WE decision

He says his and his family’s longtime involvement with the WE organization should have kept him out of the discussions

Most Read