Modern Canna Cannabis, Cannabis Testing, Contaminants

Cannabis cultivators, producers, and retailers can quickly go from making a profit on products to losing millions if a product fails safety testing. As such, ensuring that quality inputs are being used to help mitigate these failures should be an imperative part of quality processes. However, the importance of input testing is often overlooked. Throughout this blog, we will provide insight and understanding regarding cannabis bioaccumulation to better convey why input testing will help ensure that cannabis products are safe from the time the plant begins to grow roots until the final product is created and the safety data is generated by a testing laboratory. 

Why is Bioaccumulation a Concern in Cannabis?

Bioaccumulation is a process where a material accumulates chemicals or nutrients overtime. This often occurs with plants due to an inability to remove the chemicals or nutrients at the same rate that they are being introduced to their root system. Cannabis is unique in the sense that it is a hardy plant which can withstand the bioaccumulation of dangerous chemical contaminants without sacrificing the health of the plant. As such, cannabis producers must keep the potential of bioaccumulation in mind when adding nutrients, fertilizers, agricultural agents, and other media products to the plant during its life cycle. Additionally, cannabis has much lower regulatory limits for contaminants than most other botanical products, which poses an additional concern. Another issue that cannabis cultivators and producers face is that because cannabis is a product that is often concentrated through an extraction process, there is the potential for these dangerous contaminants to also be concentrated.

Over the last several years, many researchers have released scientific articles detailing bioaccumulation in cannabis and the potential risk that it poses to consumers. Many of the papers have been focused on heavy metals, however, there is also research that outlines the risk of microbial and pesticide contamination. The primary focus of this blog will be on the accumulation of metals and agricultural agents, such as pesticides, fungicides, and insecticides in cannabis.

Heavy Metals Accumulation

Cannabis has been shown to accumulate heavy metals, such as Arsenic, Cadmium, Mercury, and Lead, at high concentrations throughout the plant’s life cycle if given the opportunity. Current research has linked this uptake to be directly related to changes in physical properties such as pH and temperature, which allow the metals to travel from the soil or growth media into the root system before moving to the stems, leaves, and buds. The metals are often introduced through the growth media, fertilizers, nutrients, agricultural agents, and other chemical products that have been applied to the plant. One of the major issues with this is that cultivators are often unaware of the presence of heavy metals in products or do not understand the impact that bioaccumulation can have on the plant. As such, input testing becomes an important part of the cultivation process, helping to prevent unwanted failures in the end product.

Image Credit: Toxin Reviews

Agricultural Agent Accumulation

In addition to accumulating heavy metals, cannabis has also been shown to accumulate agricultural agents, such as pesticides, fungicides, insecticides, and plant growth regulators if the products are not used properly or if they are systemic to the cannabis plant. One of the struggles that cultivators face with using agricultural agents is that none of the products have undergone EPA approval for cannabis specifically, due to the federal status of marijuana. Therefore, cultivators are having to base their use decisions on plant types that could be similar to cannabis, such as tobacco. While most agricultural agents can be successfully removed from the plant before harvesting if they are used properly, there is a possibility that bioaccumulation can occur, especially when the chemical is in the soil or growth media. Similar to heavy metal contamination, there are instances where cultivators are unknowingly adding agricultural agents to their plants, as these chemicals are sometimes found in the soil, growth media, nutrients, and fertilizers that are used in the cultivation process.

Quality Impacts of Bioaccumulation

It is important for cannabis cultivators and producers to understand the quality impact of bioaccumulation. As previously mentioned, there are several concerns associated with bioaccumulation which may affect product quality. Ultimately, if bioaccumulation of contaminants occurs, the product may contain the dangerous chemicals at concentrations above the regulatory limit, which will prevent them from being sellable or safe for human consumption. Additionally, because cannabis flower is often used as a starting material for concentrated products, even low level contamination can become a quality concern. Agricultural agents are a great example of this because they tend to have similar physical and chemical properties to cannabinoids, meaning that they will not be removed in the extraction process, and will instead be concentrated down with the cannabinoids. Therefore, if a cultivator or producer has low level, potentially undetectable, amounts of contaminants in their flower, it could still result in a quality issue for their final product depending on the extraction technique. As such, it is important for cultivators and producers to understand the quality of their inputs to ensure that their final product meets the proper quality standards.

Input Testing for Cannabis

With the associated concerns of bioaccumulation in cannabis flower and the overall impact it can have on the quality of the final product, input testing becomes an almost necessary precaution for cultivators and producers to take to help reduce the risk of contamination and product failures. Input testing allows cultivators to fully understand the potential impact that a material being added to the plant during its life cycle may have on the final goods being produced. This testing can be done through a third party testing laboratory, who is able to screen the materials being used throughout the plant’s life cycle for potential harmful contaminants. Knowing what we do about the bioaccumulation potential that cannabis flower has, it is important to ensure that bioaccumulation of contaminants does not pose regulatory problems relating to the quality of the product. Testing labs should be capable of properly testing input materials for contaminants such as agricultural agents, heavy metals, microbials, mycotoxins, and even residual solvents. 

By performing this testing, cultivators can have a true understanding of the potential risk associated with using various fertilizers, growth media, pesticides, and nutrient mixes. It is important to note that most of these input materials will come certified and may be labeled as free of harmful contaminants, however, cultivators need to take the concentration at which those products were tested into consideration. For example, many products that are labeled as “metals-free” simply have less than one part per million (1PPM) of any one metal present, however, this could still pose a risk to cannabis producers since the regulatory limit for heavy metals in cannabis products meant for inhalation is often set at half of that concentration or less. Therefore, while the product may appear safe from the outside, there may be specific concerns for using it on cannabis due to the stringent regulatory limits that are associated with these contaminants. Ultimately, at the end of the day, the best and most cost effective way to mitigate failures that would result directly from bioaccumulation of contaminants is to thoroughly vet any and all inputs prior to utilizing them in the cultivation or manufacturing process.

References: 

Bengyella, L., Kuddus, M., Mukherjee, P., Fonmboh, D. J., & Kaminski, J. E. (2021). Global impact of trace non-essential heavy metal contaminants in industrial cannabis bioeconomy. Toxin Reviews, 41(4), 1215–1225. https://doi.org/10.1080/15569543.2021.1992444.

Citterio, S., Santagostino, A., Fumagalli, P., Prato, N., Ranalli, P., & Sgorbati, S. (2003). Heavy Metal Tolerance and Accumulation of Cd, Cr, and Ni by Cannabis sativa L. Plant and Soil, 256(2), 243–252. https://doi.org/10.1023/a:1026113905129.

Dryburgh, L. M., Bolan, N. S., Grof, C. P. L., Galettis, P., Schneider, J., Lucas, C. J., & Martin, J. H. (2018). Cannabis contaminants: Sources, distribution, human toxicity and pharmacologic effects. British Journal of Clinical Pharmacology, 84(11), 2468–2476. https://doi.org/10.1111/bcp.13695

McPartland, J. M., & McKernan, K. J. (2017). Contaminants of Concern in Cannabis: Microbes, Heavy Metals and Pesticides. Cannabis Sativa L. – Botany and Biotechnology, 457–474. https://doi.org/10.1007/978-3-319-54564-6_22.

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