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

Hudson Bay Mountain reschedules opening day for Nov. 29, citing warm temperatures, rain

The resort is asking people to upload “snow dance” videos to social media for a chance to win a hoodie

Cuts to provincial policing budget not expected to affect Smithers public saftety: RCMP

Province working with force to address project $10 million budget deficit

B.C. First Nation Chief Ed John faces historic sex charges

John served as minister for children and families under then-premier Ujjah Dosanjh

LNG Canada project gradually taking shape

Extensive worker camp now being assembled

Smithers celebrates 75th anniversary of the Netherlands liberation

Bulkley Valley Christian and Smithers Secondary schools receive gift of tulips

VIDEO: B.C. to restrict nicotine content, bring in 20% tax on vaping products

Province will also restrict candy and fruit flavoured vaping products to adult-only stores

B.C. government working with RCMP to address $10 million in budget cuts

Public Safety Minister Mike Farnworth issues statement following report of RCMP cost-cutting

‘City that protects rapists’: Sexual assault survivor slams Kelowna mayor for defending RCMP

Heather Friesen spent the morning handing out flyers around city hall calling out the mayor

BC Liquor Stores to move fully to paper bags by March

Vancouver Island to be the first to convert to paper bags in November

Tolko shuts B.C. divisions for two weeks over holidays

Head office to close from Dec. 23-27; two weeks’ downtime runs Dec. 21-Jan. 6

Port Moody mayor says stayed sex assault charge related to ‘awkward date’

Rob Vagramov said charge was related to a string of dates in 2015

UBC conference draws fire over speaker from Chinese tech company blacklisted in U.S.

The company that has been blacklisted by the U.S. over links to the repression of China’s Muslim minority

‘It’s been 12 years’: Father of murdered B.C. real estate agent pleads for mayor’s help

Lindsay Buziak was stabbed to death on Feb. 2, 2008 in Saanich. Her case is unsolved.

B.C. woman sends fight to reduce preventable medical errors to Victoria

Teri McGrath and South Okanagan senior’s centre members presented 150 signature petition to local MLA

Most Read