Cannabis Science

29 July 2022

What’s in Your Cannabis? Testing for Toxins

Studies on cannabis in the past have been sorely limited due to legality restraints on the forbidden fruit. Many scientific trials into marijuana focused on studying toxins emitted from smoking cannabis compared to inhaling tobacco. Often, research performed through the years relayed varying messages as science and technology had yet to merge.

More recent testing of toxins found within cannabis plants, however, divulges a broader scope of what’s actually in your smoke. Varying criteria such as how and where the plant is grown, not to mention the processes used to extract the potent cannabinoids, reveals a tangle of toxic possibilities.

From heavy metals in the soil to microscopic bacteria, fungi, and mould found within the plant, new challenges abound for science to discern. Throw in a complete melee of pesticide contamination and solvents used for cannabis extracts, and who really knows what’s harbouring inside the cannabis product you are purchasing.

Fortunately, science and technology are uniting as the cannabis industry unfolds, bringing forth new avenues to promote clean products for consumers. This collaboration has become increasingly prevalent as the medical marijuana industry develops. While legalization opened many doors for this emerging commerce, testing for toxins presents a whole new array of challenges.

The Growing Pains of Legalization

When many states in the US began legalizing marijuana, drug testing requirements focused on the potency of Tetrahydrocannabinol (THC) and Cannabidiol (CBD). Generally, in the early days, testing for cannabinoid percentages utilized gas chromatography (GC).

This process uses high temperatures, which change the chemical profiles of the cannabinoids, turning acidic compounds into psychoactive ones. Because of this, early potency testing data often revealed inaccurate readings as technology had yet to catch up.

Over a period of time, further developments in laboratory analysis, though, introduced high-performance liquid chromatography (HPLC) for potency testing. This method allowed for cannabinoid determination before decarboxylation. Additionally, mass spectrometry practices applied with gas chromatography (GC-MS) produced better results for potency testing.

As the cannabis industry trudged forward through legalization, many US states began implementing more rigid testing for other contaminants. Although still illegal at the federal level, some states started following commercial testing guidelines established through the Food and Drug Administration (FDA) and the Environmental Protection Agency(EPA) for food safety and agricultural practices.

Colorado was one of the first states to initiate legislation requiring producers to test cannabis flowers for toxins derived from pesticides, heavy metals, and microbiological activity. Other states, including California, Washington, DC, and Oregon, implemented similar practices as the need for testing became increasingly apparent.

On the other end of the spectrum, though, Arizona, Florida, and Illinois all passed legislation in the past few years legalizing marijuana without having any drug test requirements set forth whatsoever. Undoubtedly, one of the most significant hurdles in the US cannabis industry is the lack of governing acceptance at the federal level.

Learning More About Toxicity in Cannabis

As technology in laboratory analytics improved and science delved deeper into cannabis research, it became evident that further testing was required to ensure safety to the consumer. Cultivation practices, especially on the commercial level, produced an array of hurdles for the producer to overcome.

Additionally, extraction processes for concentrates presented solvent-based toxicities to eliminate. While commercial cannabis producers began to dial in cultivation and post-harvest practices, eliminating toxicity in cannabis plants became a considerable challenge to overcome.

The Environment and Microorganisms

Cannabis plants love warm, humid growing conditions. Unfortunately, so do all kinds of microbial pathogens. Fungi and mould-producing mycotoxins such as aflatoxin spores nestled deep within thick colas are a toxic disaster post-harvest. Further investigation into microorganisms found that salmonella, E. Coli, Mold, and Yeast tend to harbour in marijuana plants.

Soil and Heavy Metals

Outdoor growers in some regions discovered the soil they were growing in retained toxins. As a result, heavy metals such as arsenic, cadmium, lead, and mercury began showing up in tests as a routine procedure in acquiring soil samples.

Cannabis plants efficiently uptake heavy metals through their intricate root system and deposit them throughout their tissue. Testing for these toxicities in parts per million (ppm) became paramount, especially as the medical marijuana industry became energized.

Pesticide UseWhen legalization first began, many inspiring entrepreneurs opted to grow their crops indoors. Large commercial greenhouses and other renovated warehouse facilities began popping up in legalized areas. Unfortunately, many growers were unaware of the pest populations that can infiltrate indoor grow operations.

While pesticide use is routine in many agriculture practices, there were no guides or application rates for cannabis growers to follow in the beginning. Growers soon learned they had to mix several different insecticides and fungicides to combat the invasive pest problems associated with this new agricultural crop.

Most states in the US that have legalized marijuana use today reveal a long list of restricted pesticide products for use in cannabis cultivation. Testing for these toxic chemicals is an essential mandate, especially for public health and medical use.

Extraction Processing for Concentrates

Extraction processes to isolate cannabinoids and terpenes for use in oils, edibles, vaping, and other marijuana products typically use solvents such as butane, propane, and other flammable hydrocarbons. Early extraction operations utilizing these toxins often left residual solvents in the final product. Testing for these toxic inputs became inclusive in state testing guidelines as the nascent concentrate sector of cannabis users took a strong foothold.

The Testing Snag

When states first began legalizing marijuana, very few laboratories offered cannabis testing services. While labs existed for medical purposes, food, and agriculture needs, few technicians had hands-on experience analyzing this plant. However, it didn’t take long for quick-acting business owners to capitalize on this new industry sector.

Cannabis testing labs began springing up, offering testing services with their established protocol and instrumentation to perform the tests. The snag in testing arose as laboratories applied different equipment for analysis. Whereas one lab may use GC for potency, another processed their findings through HVLC. Often, the results were vastly different.

There were minimal standards and no quality control established for testing procedures, leaving a wide margin of differentials in the cannabis testing community. As producers began realizing the discrepancies in lab test results, they learned to shop around to get the best results, cherry-picking plant material to achieve optimal results for higher THC levels.

In addition, each state has its’ own agenda for testing requirements. For instance, some states require testing for heavy metals, while others omit that from their rules.

Testing Requirements Around the World

As the worldwide frontrunner in cannabis legalization, Canada prepared for the transition well ahead of the game. Legalizing hemp in 1998, followed by medical cannabis in 2001, Canada became the first country to approve recreational use nationwide in 2018. Canada set the stage for protocol long before they enacted legislation.

Setting up standardized practices through the national regulating system titled Health Canada, the forward-thinking Canadians outlined exact procedures on a national level to help guide the country through legalization. Laboratories, cultivators, and extraction processors had standards to follow, allowing a base for the cannabis industry to succeed.

While other countries such as Australia, Germany, the UK, Israel, Brazil, and others have legalized medical cannabis in recent years, most of them currently do not have established guidelines in place to test for toxins in cannabis. However, market research into this emerging industry predicts a surge in laboratory testing in the next several years as legalization continues to unfold around the world..

What the Future Holds for Testing

While individual state testing requirements vary considerably around the country, a need for accreditation in cannabis testing is becoming increasingly clear. By providing consistent standards and third-party verification, many states now require testing laboratories to follow the International Organization for Standardization ISO/IEC 17025.

This accreditation program sets requirements for impartiality and risk assessment while evaluating measurement uncertainty in laboratory environments. The goal in creating this program is to foster confidence in laboratory operations, offering standards for all industries to follow, including cannabis.

More recently, the National Institute of Standards and Technology (NIST) is working to develop a measurement service program to promote quality in cannabis testing analysis. Their goal is to establish continuity in lab testing with supportive measures in analytical methods, providing reference materials, and implementing the Cannabis Quality Assurance Program (Canna QAP).

While talks of US federal government legalization hover on the horizon, a generalized set of testing standards will ultimately help guide the evolving cannabis industry. Until then, states must determine their best practices with increased awareness through scientific research and, more importantly, the cannabis community’s support.

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Post author
Charle Thibodeau
Charle’ Thibodeau is a freelance writer with almost a decade´s experience, specializing in cannabis content for the past two years. A strong motivation to educate, inform, and promote the culture surrounding this miraculous plant is her earnest mission.
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