Don’t Let Contaminants Spoil the Cannabis Supply Chain

Posted March 12, 2019

Given the flurry of recent cannabis product recalls in California, Colorado, Michigan and elsewhere, itâ€™s not surprising that pesticide testing is under great scrutiny by state regulators. Whether the culprits, unwitting or not, are the cultivators delivering tainted cannabis to dispensaries or dispensaries selling tainted products to consumers, the dangers are real from not only human safety considerations but also a financial business standpoint. Some industry analysts say that product recalls can amount to ten figure losses along the supply chain¹.

Letâ€™s take a quick look at the offending compounds:

Mycotoxins: Like many other agricultural crops, cannabis plants are susceptible to contamination by mycotoxins during cultivation, storage or processing.Â Mycotoxins are a group of carcinogenic toxins produced by certain species of fungi and mold.

Pesticides: Pesticides, herbicides, fungicides, growth regulators and other products are used to either protect crops from pests or help increase yields. Most are harmful if ingested and the safety risk for inhalation is largely unknown. Every state regulates the type and amounts of pesticides that can be used.

Heavy Metals:Â Toxicity occurs when a plant is grown in soil that is already contaminated with heavy metals, such as lead, mercury, arsenic, cadmium, chromium and others. The heavy metals are then taken up by the plant and toxic if ingested.

Of all the mandated cannabis safety and compliance tests, residual pesticide analysis is particularly challenging due to the highly complex cannabis matrix. Pesticide residues have been found in various products, including flowers/buds, concentrates, and infused edibles. Each state with legalization laws for cannabis use for medicinal and/or recreational purposes has established policies for pesticide use and acceptable levels. For example, Oregon was one of the first states in the U.S. to issue comprehensive guidelines for pesticide residues analysis in cannabis, and set regulatory limits for 59 pesticides. California issued more stringent action limits (about a factor of 2 to 20 lower than Oregon state action limits) for 66 pesticides (including all but one of those found on Oregon state list, and eight more) and five mycotoxin residues in cannabis flower and edibles².

From a testing standpoint, pesticide analysis is quite complex and requires expensive, sophisticated laboratory instrumentation and expert analysts trained in using the instrumentation and interpreting the results. For example, mycotoxins can be identified and detected in the field or lab at the parts-per-billion level using immunoaffinity columns coupled with fluorescence detection, High Performance Liquid Chromatography (HPLC), or Liquid Chromatography-Mass Spectrometry (LC-MS) techniques. Analytical testing with LC-MS and LC-MS/MS and Gas Chromatography-Mass Spectrometry (GC-MS and GC-MS/MS) techniques are used to identify and quantify pesticides. And, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) can be used to identify trace level heavy metals.

My recommendation is to carefully review and gain a thorough understanding of your state limits and regulations for contaminant testing and make sure that you have the scientific equipment and expertise to perform the tests yourself or through certified testing labs.

Dr. John A. MacKay, PhD