Recent Workshop Emphasizes Why the Cannabis Industry Needs to Get Better at Measuring Heavy Metals

Unfortunately, there are many inconsistencies with heavy metal limits in different states where cannabis is legal. Most define four heavy metals (Lead, Arsenic, Cadmium, Mercury) while others specify up to nine. Some are based on limits directly in the cannabis plant, while others are based on human consumption per day. Others take into consideration the bodyweight of the consumer, while some states do not even have heavy metal limits. Some states only measure heavy metals in the cannabis plant/flower, while some give different limits for the delivery method such as oral, inhalation, or transdermal.

It was these regulatory inconsistencies, which led me to explore the possibility of writing a book on the topic. I had spent the last three years working on another book which focused on the measurement of elemental impurities in pharmaceuticals and was looking for a new project when one of my contacts suggested I take a look at the cannabis industry. It took me a few months of research and interviewing key players in the industry including cultivators, growers, processors, manufactures, state regulators, and testing labs to realize that heavy metals were not high on their priority list. One cultivator even accused me of being an investigative journalist, when I asked them if they knew what elemental contaminants were in their products.

Over the next few months, I started going to cannabis science meetings, conferences, and trade shows and noticed there were never any talks on heavy metals. When I began digging up information in the public domain about the hyper-accumulating properties of the cannabis plant, I realized that this was a topic that urgently needed to be addressed. My research eventually connected me with the MMCC which was responsible for regulating all sales of medical cannabis in the state of Maryland. As a result, I got a much better understanding of the extremely difficulty job that regulators had. They ensure that all cannabis-related products are safe for human consumption and that all the independent testing labs in the state of MD are generating high-quality data for all the critical analytes, including potency and contaminants such as residual solvents, pesticides, microbes, and heavy metals.

My interviews had also highlighted the inexperience and lack of knowledge of many of the testing labs that had sprung up in the past few years, because the industry was growing at such an alarming and chaotic pace. I felt that this was a great opportunity to make a difference and help the industry, so over the next few months I began to put together the agenda for a one-day educational workshop, the Optimization of ICP-MS for Measuring Heavy Metals in Cannabis, for the testing labs in the area that didn’t have a good understanding of working with the technique.

Fast forward to October 3rd, 2019 at the Sheraton Hotel in Columbia, Maryland, where we attracted an audience of over 50 people, made up of federal, state, private, and academic analytical testing lab personnel. The day was jam-packed with advice, tips, methods, guidance, troubleshooting, suggestions etc. on how to optimize the use of ICP-MS for the accurate and validated measurement of heavy metals in cannabis and cannabis-related products.

After Lori Dodson from MMCC had welcomed everyone, I kicked off the scientific part of the meeting, by talking about the early days of ICP-MS when I worked on the very first commercially-available instrument, the ELAN 250 in 1983 and the difficulty in generating sample ions in the plasma and the challenge of getting them into the mass spectrometer for separation and detection. I also talked about the fundamental principles and the most common application areas of the technique. We heard from:

• Shimadzu’s Dr Andrew Fornadel who talked about the challenge of using ICP-MS to characterize the different kinds of cannabis-related samples.
  
  
• Patti Atkins, from Spex CertiPrep, a manufacturer of standards and reference materials, talked about good laboratory practices and how to reduce and minimize sources of contamination in ICP-MS.
  
  
• Laura Lawlor from Milestone, Inc., a manufacturer of microwave sample digestion systems, spoke on the selection of the optimum digestion approach for cannabis samples and the use of clean chemistry solutions to ensure clean blanks.
  
  
• Dr Ryan Brennan and Justin Masone, of Glass Expansion, manufacturers of ICP-OES/ICP-MS sample introduction components, presented on maintenance procedures and ways to enhance sample throughput.
  
  
• Dr Steven Pappas, from the Tobacco Inorganics Group of the Centers for Disease Control and Prevention (CDC), talked about testing electronic nicotine delivery (END) vaping devices for heavy metals and what he has learned about the corrosion of the metallic components inside the devices that could be applied to cannabis vaping pens.
  
  
• Lawrence Neufeld, CEO of Spectron, Inc., a cone manufacturer, discussed ICP-MS cone maintenance and cleaning for enhanced instrument lifetime.
  
  
• And finally, Dr Melissa Phillips, from the Chemical Sciences Division of the National Institute of Standards and Technology (NIST), spoke about the urgent need for quality assurance programs and Certified Reference Materials (CRM) to ensure robust validation protocols for the accurate measurement of all analytes in cannabinoids.
  
  
• Outside of the agenda we also heard from Dr. Nandu Sarma, the Director of Herbal Medicines at the United States Pharmacopeia (USP). Dr Sarma was in attendance and asked if he could say a few words about USP's position on standard methods for the analysis of cannabis and hemp.
  
  

It was a long day, but well worth it. The feedback we got from the attendees was very encouraging. There is no question that most of the audience left the workshop with a far greater appreciation of what it takes to get good data by ICP-MS. However, the industry will always be faced with the fact that typical operators only have a couple of years’ experience at most and some of them just a couple of months’. For that reason, it’s always going to be challenging for these operators who are not used to working in the ultra-trace environment but are also working in labs that in most cases were not designed for ultra-trace elemental analysis.

I have had requests to do similar workshops in other parts of the US, but as I did this one pro bono, there’s the issue of funding for future workshops. However, we recorded all the talks and linked them digitally to the PowerPoint slides so there might be opportunities to use them for training purposes. I’m firmly convinced that educating the industry is of critical importance. The people who are trying to raise the bar today will be rewarded when the federal regulators eventually come knocking on the door. As a result, I’m hoping to play a big part in helping the industry better understand the many sources and role of elemental contaminants in cannabis products, which will eventually lead to safer products for consumers.

Article contributed by Robert Thomas, Scientific Solutions, Gaithersburg, MD.