Health Canada updates pesticide testing requirements in wake of new results

Testing completed at seven locations, with two coming back showing detection of pesticides on leaves

Today Health Canada announced the results of a new inspection and testing program in the wake of several pesticide-related recalls in the last six months. The regulator also announced that it will now require all licensed producers to conduct mandatory testing of all cannabis products destined for sale for the presence of unauthorized pesticides.

Preliminary results from seven surprise inspections and 43 random samples show, of seven different leaf samples taken, two came back showing the presence of unapproved pesticides and a known ingredient in pesticides. Leaf samples were taken from cannabis plants in various stages of growth and tested at parts per billion. Testing of dried cannabis and cannabis oil samples taken from the seven licensed producers is ongoing and the results are not yet available.

Health Canada says they “collected samples of plant leaves, dried cannabis and cannabis oil (if produced), as well as samples of any products suspected to contain pesticides the inspectors found on site.”

The testing was completed on May 1st and 4th by Health Canada’s Pest Management Regulatory Agency at seven different sites: RedeCan, 7Acres, Tweed, Tilray, Broken Coast, Hydropothecary and Peace Naturals. The first five passed testing, while Hydropothecary and Peace Naturals did not.

According to Health Canada, “both leaf samples at Hydropothecary tested positive for myclobutanil at low level concentrations of between 0.012 and 0.023 parts per million (ppm), and one leaf sample from plants at Peace Naturals tested positive for piperonyl butoxide at a low level concentration of 0.78 ppm.” Piperonyl butoxide (PBO) is an organic compound used as a component of pesticides and found in many insecticides approved for use by Health Canada. 

Health Canada announced their new testing program last February after products from two different licensed producers were found to have the presence of myclobutanil and/or bifenazate, both unapproved pesticides for cannabis in Canada. As of May 2, only 17 pesticides are approved for use on cannabis in Canada by the Pest Management Regulatory Agency (PMRA).

Dr. Shane Morris, the Vice-President and Quality Assurance and Scientific Affairs Officer at Hydropothecary, says the Quebec producer has been doing its own internal testing, which showed no levels of pesticides below any detectable levels at 50 parts per billion. Health Canada’s testing went to 10 parts per billion, although Morris says this was without without notice or consultation. Hydropothecary has been posting all their own internal pesticide results on their website. 

Representatives for Peace Naturals said they will be posting a response on their website soon but refused statement. Editor's Note: This article originally stated Peace Naturals was unsure of where the pesticide precursor came from. This was inaccurate.  Peace Naturals have now provided a comment saying:

"Peace’s root cause analysis indicates that this was the result of cross-contamination from a sanitation protocol that is no longer practiced at Peace. The sanitation protocol has not been practiced since new management implemented an improved production methodology after taking control of Peace. The source of the PBO was a PMRA approved product that was used to sanitize empty rooms between harvests."

"There is no evidence to suggest that PBO at these levels is likely to cause any adverse health effects when inhaled or ingested. However, out of an abundance of caution, Peace is in the process of assessing which lots have been impacted, notifying patients, and will voluntarily recall any products that have even potentially been implicated."


OrganiGram, Mettrum and Hydropothecary all say they are unaware of how the unauthorized pesticides made their way into their supply chain. One possible theory floated by some is that myclobutanil, being a systemic pesticide, could be transferred from a mother to a clone and could stay in the plant's system for 3 months. If a mother plant or clone was treated, even prior to coming to a facility, it’s possible the leaves of the plant could still test positive, especially when testing at parts per billion.

“If you applied a systemic insecticide … then a week later you take cuttings, depending on the solubility of the systemic ... it probably would end up in those clones at some concentration” says Raymond Cloyd in a recent article. He is a professor at the entomology department at Kansas State University, with specialties in horticultural entomology and plant protection.

Lift contacted several analytical testing labs listed by Health Canada to discuss testing for pesticides on cannabis. While all said the idea of it being passed on through cuttings, systemically, seems slim, several other theories have been proposed, such as it coming through the air from nearby fruit and vegetable farms, or from incidences of it infiltrating the existing water system in areas of high agricultural use.

False positive from terpenes?

Hubert Marceau, the Director of Development at Laboratoire PhytoChemia Inc. in Québec, says this theory is possible, noting the half-life for myclobutanil is about 300 days. But he personally doesn’t think it’s all that likely. His concern, echoed by others in the field, is to better understand the methodology used by Health Canada to determine these levels. Depending on the methodology, he explains, it’s very possible there could be a false positive triggered by certain terpenes.

“It’s an interesting theory, but I would be quite surprised because as everything is metabolized and the plant grows, the levels would go lower and lower. But parts per billion is ten thousand parts less than points per million. So it’s possible.”

Marceau’s question, he explains, has more to do with the lack of transparency around the methods and standards Health Canada is using. Without knowing how Health Canada is testing, and to what level, it’s difficult to vet the process, he says. Especially when so many cases are arising where there is no known source for the unauthorized pesticides.

“One of the things that I am wondering is are they sure this isn’t a false positive,” says Marceau. “As most know, cannabis produces a lot of terpenes and we have seen some false positives with terpenes and pesticides in some older methods. So if the methods aren’t published, there’s no way a third party could check that methodology. We still need to rely 100% on Health Canada with that.”

In the air or water?

Sohil Mana, Vice President of operations at Eurofins Experchem Testing Labs, a major testing lab in Ontario, says he also doesn’t think it’s likely the pesticides have made their way into the supply chain systematically through clones treated, but he does say it’s possible they infiltrated either the local water supply or even traveled through the air from nearby farmland.

“It doesn't mean the company itself is spraying the product. It could be from greenhouses that are attached through other farmland, and then it seeps into the water system, and that’s what you tend to find. The spray, when it goes in the air, it could travel miles and miles.”

Mana says part of the problem is that initially, Health Canada encouraged the use of methods like USP 561 (US Pharmacopeial Convention), which most labs and producers adopted. The reality of the methodology, explains Mana, is that it does not contain all the possible pesticides.

Like Marceau, Mana says he is supportive of Health Canada’s approach to testing, but wants to see the methodology and limits made public. As equipment improves, it will always be possible to detect lower and lower levels, he explains, so establishing industry standards for acceptable limits, and basing these limits on clinical trials, is important.

“What's going on,” explains Mana, “is Health Canada looks for the very lowest limit available that the equipment can provide. I wish they would provide limits and methods, but that’s not what they do. They set out the regulations and then the industry has figure out the best practices.”

Eurofins purchases $1 million in new pesticide testing equipment for cannabis

To address this, he explains, Eurofins has recently purchased over a million dollars in new testing equipment that will test for very low levels of pesticides, covering almost 500 of them. This was specifically for the medical marijuana industry, he says. They purchased a tandem liquid chromatography–mass spectrometer (LCMSMS) and a tandem gas chromatography-mass spectrometer (GCMSMS). Read more on these methods here.

“We have actually purchased LCMSMS and GCMSMS, the most sensitive equipment on the market" says Mana. "So we invested about $1.1 million just two weeks ago, to be able to test very low levels of pesticides. And this is bought intentionally for medical marijuana.”

“That’s why we bought this equipment, to show the industry, ‘hey, there’s a better way of doing this than the way you’re doing currently.’”

“What Health Canada is doing is great,” continues Mana. “I’m very happy about it, because the idea is, how do you control growers from doing things either intentionally or unintentionally: how do you control them? The only way to do this is to take samples from the facility, test them, and [provide] the results.”

“What the government should also do is provide methodology: ‘This is the way we’re going to do things and these are the instructions to follow.’”

The Office of Medical Cannabis communicated to one licensed producer that their testing levels are in line with international best practices of .01 parts per million (ppm), but that in some instances the regulator may test at a higher limit depending on several additional factors, stating: "In some instance, the reporting limit could be higher due to a number of factors such as the characteristics of the active ingredient, the complexity of the sample matrix, instrument sensitivity and analytical methodology."

For reference, one ppm is 1 part in 1 million. 0.01 ppm is ten parts per billion (ppb). One ppm is comparable to one second in 11.5 days or four drops of ink in one 55-gallon barrel of water.

Health Canada has recently disallowed the use of foliar sprays for cannabis producers, a move some say is to prevent anyone from applying unauthorized pesticides under the guise of fertilizing via foliar feeding. However, Health Canada still allows for fertilizers and supplements to be applied to plants via their roots. Arguably, a pesticide like myclobutanil could also be applied in this way.

More from Lift on this issue as it evolves. 

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1 comment

  1. Robert Reply

    How about no Chemicals period grow organic.