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Heavy Metals Contamination: Is Cannabis Packaging to Blame?

By Roxanne Newman

Published: Feb 20, 2020   
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Heavy metal testing for cannabis products has gained significant momentum in the past 12 months, not only due to a link identified between the recent outbreak of vaping related illnesses and heavy metals exposure. However, instead of just focusing on testing the raw cannabis material, there has been significant evidence that leachability from packaging may also be to blame.

Analytical Cannabis caught up with Jini Curry, laboratory director of Modern Canna Labs, to learn more. 

Roxanne Newman (RN): How and why did you enter the cannabis industry?

Jini Curry (JC): Like many in this field, if you asked me five years ago if this is what I thought I would be working on, I would have told you that you were crazy. However, when this opportunity arose it was one that I could not pass up. Those who are in this industry are the pioneers and we are going to be the ones who break the negative stigma that goes along with the word cannabis.

There are many individuals who do not understand the importance of testing cannabis for contaminants or what consequences will accompany the sale of ‘bad product.’ In order to change the way that people view cannabis, we need to ensure that the products which are being sold are truly helping those using it, rather than harming them.

My goal in this industry is to help develop standardized methods which can be used nationally and internationally to ensure that cannabis is safe for consumption.

RN: Why is heavy metal analysis so important for cannabis?

JC: Heavy metals analysis is crucial for cannabis due to the dangers that are associated with the consumption or inhalation of these compounds. Heavy metals poisoning can occur if metals such as arsenic, cadmium, lead, and mercury, which are referred to as ‘The Big Four,’ accumulate in the body. If products that are being consumed contain high amounts of any of these compounds, the outcome can be extremely dangerous and serious health problems can arise.

Another reason why this testing is so important is because cannabis is an accumulator plant, which means that it can survive in environmental conditions that many other plants would not thrive in. Many plants and crops cannot survive if there are excessive amounts of any one metal present. The metal will deprive the plant of nutrients and it will eventually die. However, cannabis simply absorbs those metals and allows them to become concentrated in the plant.

If heavy metals analysis is not being conducted on the raw material or the final product the consumer has no way of knowing whether the product contains any of the dangerous heavy metals which may have accumulated over the plant’s life cycle.

RN: Is there a preferred method for testing heavy metals?

JC: Heavy metals testing has been conducted in the environmental industry for many years and the Environmental Protection Agency (EPA) has standardized methods which they have established to conduct this testing. Using our background knowledge in the environmental industry, our laboratory was able to use those methods, with the appropriate modifications, to establish a preferred testing method for cannabis.

The standardized methodologies which we have based our method on are EPA Method 6020B and EPA 3051A. EPA 6020B uses an inductively coupled plasma with mass spectrometry to detect metals in concentrations that are sub-ug/L in fully digested samples. EPA 3051A uses microwave assisted acid digestion to prep samples which are not already in solution, such as, flower, distillate, wax, shatter, tinctures, and even edibles.

The food, pharmaceutical, and environmental industries have been conducting testing for many years and labs should not try to re-invent the wheel. At its root, cannabis is a plant and for this reason I wholeheartedly believe the methodologies used to analyze cannabis should be developed from EPA methodology.

RN: How can you ensure accuracy and precision in heavy metal testing?

JC: Quality control, quality control, quality control – I cannot stress this enough. In order to trust data that is being reported by a testing laboratory, they should be able to present quality control data that shows that the results they obtained are reproducible, reliable, and defensible. Our laboratory prides ourselves on the fact that we never release data that we are not 100 percent confident about. Full quality control is analyzed with each analytical batch, and the data is evaluated with high scrutiny to ensure that the results are not in question.

For metals specifically, the following quality control should be included to ensure that the data obtained is accurate. A method blank, laboratory control sample, duplicate, matrix spike, and continuing calibration verifications should be run at a minimum.

RN: What does the future have in store for cannabis testing and specifically heavy metals testing?

JC: As more states and countries pass laws regarding the recreational use of cannabis, I believe that the importance of testing is going to rapidly increase. One of the main issues that many individuals have with cannabis is that they believe it is not safe for human consumption. In order to break that stigma, analytical testing needs to be performed on all products prior to sale.

To keep up with the testing demand, laboratories all over the world will need to have the capability to analytically test product and produce validated results regarding what contaminates may or may not be present.

For heavy metals specifically, testing is going to be of a greater importance due to the use of vape cartridges. There are many news outlets which are claiming that the use of vape cartridges containing cannabis are leading to mysterious and deadly illnesses. To determine if cannabis contains any heavy metals the product needs to be analyzed from its final packaging material.

The reason behind processing samples in this manner, is to ensure that heavy metals are not leaching from the packaging. We have seen many instances in our laboratory where samples will be tested prior to packaging and then again after packaging and the results vary between tests.

We have since linked this phenomenon to heavy metals leaching from the packaging into the product, which is then consumed by the user. For this reason, it is going to be imperative that the final product in its packaging is tested, for heavy metals at a minimum.

RN: Do you have any words of wisdom for other testing labs?

JC: Always ensure that your data is reliable, reproducible, and defensible. In a world where people are consuming the product you are testing, there is bound to be questions regarding your results at some point in time.

As a laboratory, you should always be prepared for this possibility.

Running full quality control with each analytical batch is the best practice for combating any questions that may arise regarding the accuracy and precision of the data that is being produced.

Roxanne Newman

Team Lead, Conference Production

Roxanne joined Analytical Cannabis in 2019 as conference producer, where she helps to organize our webinars, online symposia, and physical events in Europe and the US. She graduated from Anglia Ruskin University in 2019 with a 1st class Bachelor's in Biomedical Science and was also awarded the Undergraduate Prize for Physiology from the Physiological Society, London. During her studies, Roxanne also received a prestigious summer research studentship to investigate the effect of natural products on the gut epithelial.


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