Tag Archives: toxic


Cannabis Industry Needs Leadership, Not Pesticides

By Ben Ward

The medical cannabis sector is currently attracting increased attention, as patients, doctors, regulators and investors take a closer look at our industry. There is a lot for them to learn and to benefit from as our industry matures under the glare of the proverbial spotlight. And there’s a lot for those of us in the industry to be proud of. We’re helping patients manage pain, for example. We’re helping them get their lives back.

But that same spotlight is also revealing some problems in our industry.

Take ingredients for example. When I look at the ingredient list in my natural medicines, I don’t expect to see Myclobutanil, Piperonyl Butoxide, Pyrethrin, Bifenezate, and Avermectin listed. Yet, that’s exactly what some licensed producers of cannabis in Canada and some cultivators in California have been selling to their patients. You have to ask yourself why, when pesticides are the only toxic substances released intentionally into our environment to kill living things. Patients don’t take cannabis to harm themselves. They do it to improve their quality of life.

Yet some cannabis companies have violated their patients’ trust in supplying them with something that could harm them. Indeed, recalls for cannabis, unfortunately, are now becoming somewhat commonplace on both sides of the border. These licensed producers – audited and approved by government – are entrusted to produce safe, reliable, consistent medicine for patients. They are entrusted to put safety at the core of their business at all times. But that is clearly not the case in certain circumstances.

In the past year, a few of the 52 licensed producers in Canada have been found to have pesticide contamination in their cannabis products. From what I can see, the explanations given for the presence of these pesticides don’t make sense. Pyrethrin, for instance, has been found on some medical cannabis products shipped out of certain growing facilities. However, pyrethrin does not naturally appear on plants. It has to be intentionally applied, accidentally or otherwise.

That means, in cases where this pesticide has been found on products after they left the growing facility, two things had to have happened. First, someone introduced it onto the plants to deal with an insect infestation. And second, lax quality control standards – perhaps influenced by a short-term focus on profits over patients – allowed infected products to enter their supply chain and, in many cases, to be consumed by patients.

When revealed, those responsible for companies using pesticides such as pyrethrin say they are “shocked”, publicly declaring that they have no clue as to how these toxic substances entered their cultivation processes. The fact is, if you don’t test your inputs, if you fail to test your outputs, and if you manage your business for short-term profits, you shouldn’t be producing cannabis.

There’s no place in healthcare for people who disregard a patient’s well being, because – from a patient’s perspective – what you don’t know could hurt you. No one who grows something can absolutely guarantee that a mistake will never be made, granted. But as the cannabis sector expands, experienced cannabis firms know there’s a direct correlation between attention and leadership: as the world pays more attention to our sector, the onus on us to be stewards in and for our industry also rises.

That means putting patient safety at the centre of everything we do. And that means ensuring patients are consuming safe cannabis produced by licensed companies that are committed to the long-term health and prospects of our growing industry.

The Practical Chemist

Instrumentation for Heavy Metals Analysis in Cannabis

By Chris English
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Determination of Toxic Metals in Cannabis

Heavy metals are common environmental contaminants often resulting from mining operations, industrial waste, automotive emissions, coal fired power plants, amount other sources. Several remediation strategies exist that are common for the reduction/elimination of metals in the environment. Phytoremediation is one method for removing metals from soil, utilizing plants to uptake metals which then bioaccumulate in the plant matter. In one study, cesium concentrations were found to be 8,000 times greater in the plant roots compared to the surrounding water in the soil. In 1998, cannabis was specifically tested at the Chernobyl nuclear disaster site for its ability to remediate the contaminated soil. These examples demonstrate that cannabis must be carefully cultivated to avoid the uptake of toxic metals. Possible sources would not only include the growing environment, but also materials such as fertilizers. Many states publish metal content in fertilizer products allowing growers to select the cleanest product for their plants. For cannabis plant material and concentrates several states have specific limits for cadmium (Cd), Lead (Pb), Arsenic (As) and Mercury (Hg), based on absolute limits in product or daily dosage by body weight.

Analytical Approaches to Metals Determination

Inductively Coupled Plasma, Ionized Argon gas stream. Photo Courtesy: Sigma via Wikimedia Commons

Flame Atomic Absorption Spectroscopy (Flame AA) and Graphite Furnace Atomic Absorption Spectroscopy (GFAA) are both techniques that determine both the identity and quantity of specific elements. For both of these techniques, the absorption in intensity of a specific light source is measured following the atomization of the sample digestate using either a flame or an electrically heated graphite tube. Reference standards are analyzed prior to the samples in order to develop a calibration that relates the concentration of each element relative to its absorbance. For these two techniques, each element is often determined individually, and the light source, most commonly a hollow cathode lamp (HLC) or electrodeless discharge lamp (EDL) are specific for each element. The two most common types of Atomic Emission Spectroscopy (AES) are; Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and ICP-Mass Spectrometry (ICP-MS). Both of these techniques use an argon plasma for atomization of the sample digestates. This argon plasma is maintained using a radio frequency generator that is capable of atomization and excitation of the majority of the elements on the periodic table. Due to the considerably higher energy of the plasma-based instruments, they are more capable than the flame or furnace based systems for measurement of a wide range of elements. Additionally, they are based on optical emission, or mass spectrometric detection, and are capable of analysis of all elements at essentially the same time.

Technique Selection

Flame AA is easy to use, inexpensive and can provide reasonable throughput for a limited number of elements. However, changes to light sources and optical method parameters are necessary when determining different metals. GFAA is also limited by similar needs to change the light sources, though it is capable of greater sensitivity for most elements as compared to flame AA. Runtimes are on the order of three minutes per element for each sample, which can result in lower laboratory throughput and greater sample digestate consumption. While the sensitivity of the absorption techniques is reasonable, the dynamic range can be more limited requiring re-analyses and dilutions to get the sample within the calibration range. ICP-OES allows the simultaneous analysis of over 70 elements in approximately a minute per sample with a much greater linear dynamic range. ICP-OES instruments cost about 2-5 times more than AA instruments. ICP-MS generally has the greatest sensitivity (sub-parts-per-trillion, for some elements) with the ability to determine over 70 elements per minute. Operator complexity, instrument expense and MS stability, as well as cost are some of the disadvantages. The US FDA has a single laboratory validated method for ICP-MS for elements in food using microwave assisted digestion, and New York State recently released a method for the analysis of metals in medical cannabis products by ICP-MS (NYS DOH LINC-250).

The use of fertilizers, and other materials, with low metal content is one step necessary to providing a safe product and maintaining customer confidence. The state-by-state cannabis regulations will continue to evolve which will require instrumentation that is flexible enough to quickly accommodate added metals to the regulatory lists, lower detection limits while adding a high level of confidence in the data.