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Heavy Metals, Heavy Responsibilities for US Cannabis Testing Labs

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The cannabis revolution in the US has had a profound impact on analytical testing laboratories.


Soaring demand for cannabis derived-products and the ongoing legalization of the drug across individual states have placed complex and weighty new demands on the nation’s analytical scientists.


Many labs - whether new set-ups or established institutions - have found themselves scrambling to keep up with continually evolving testing methods and regulations for contaminants such as heavy metals and pesticides. Often, the need for certainty - in guaranteeing accurate results, maintaining quality assurance, and providing a reliable service to customers - conflicts with rapidly-changing developments outside the lab. For laboratory owners and managers, the headaches include stricter yet widely differing testing requirements across states, as well as tight budgets and time pressures.


One of the fundamental challenges facing the laboratories responsible for ensuring that cannabis is free from heavy metals and other contaminants is the very nature of the product. The cannabis plant is a hyper-accumulator of heavy metals in the soil, absorbing trace elements from growing mediums, soils, fertilizers and even metallic equipment used during commercial processing. In some US states, the recent tightening of regulatory and testing regimes has already provided sobering evidence that the ‘big four’ heavy metals - lead, mercury, cadmium and arsenic - may be more present in cannabis products than we thought. For example, in February 2019, a batch of marijuana containing arsenic and cadmium was recalled from a Michigan medical store. In the same month, the introduction of extensive new testing regulations for heavy metals in California was followed by local laboratories reporting worrying levels of lead contamination in some popular cannabis vaping cartridges. The many potential suspects for the California contamination included not just soil-borne heavy metals, but also the potential addition of lead during the cartridge manufacturing process in China. Lead leaching from metal components via cannabis oil was another potential hazard, as were faulty laboratory testing processes that might inadvertently contaminate previously ‘clean’ samples.


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Faced with a rapidly-changing industry, both cannabis growers and testing laboratories need to ensure that their processes keep pace with new developments and regulations – as well as maintaining high standards and employing the best materials. Cultivators need to be cognizant of heavy metals, but analytical chemistry laboratories will play the critical role in ensuring that all cannabis products are comprehensively tested – providing an accurate picture of CBD, THC and terpenoid levels, as well as hazardous trace elements.


The toxic effects of heavy metals on humans – including cancers, neurological damage, kidney disease and learning disabilities - are already well known. Which makes it even more surprising that the regulatory mechanisms for the US cannabis industry are so varied and, in some cases, non-existent.


Cannabis statutes are currently the responsibility of individual states, and differ widely between territories such as, Delaware, Illinois and Oregon - where there are no regulations mandating specific tests for heavy metals - and jurisdictions like California, Florida and Washington DC, which demand a rigorous range of analyses.


California requires all cannabis to be tested for cannabinoids, terpene content, heavy metals and mycotoxins, in addition to moisture content, residual solvents, pesticides and microbial impurities. In Maine, the scene changed rapidly in September 2019, when emergency legislation was introduced to set specific testing protocols for medical marijuana, including limits on heavy metals.


Maryland also amended its statute book to order testing for heavy metals in medical cannabis after the deaths of more than 60 people in the 2019 EVALI outbreak - and included inorganic contaminants outside of the big four (chromium, manganese and nickel) on its list.


With states’ legalisation and testing pictures in various states of flux, there is also the prospect that the federal Food and Drug Administration (FDA) could decide to take a bigger role in regulating the safety of the burgeoning cannabis industry. Last year, the FDA said it was concerned that a lack of appropriate processing controls and practices could put consumers at risk, and promised to investigate reports of CBD potentially containing unsafe levels of contaminants, such as pesticides and heavy metals.


Given the triple challenge posed by rapid industry growth, serious safety concerns and a fragmented, fast-changing regulatory picture, it is crucial for both cannabis growers and laboratories to prepare now for what the future may bring. Quality and innovation are likely to be key, as laboratory and quality control managers will need to partner with trusted reference materials (RM) providers who can also keep them up to date with the latest regulations and industry news.


Dr Ehrenstorfer’s complete cannabis portfolio provides a broad offering of reference materials.


As part of the LGC Group, we can also offer you the opportunity to participate in the AXIO Proficiency Testing scheme for the cannabis industry. For 40 years, AXIO has been a trusted partner for laboratory professionals working to keep products safe for everyone.


To view Dr Ehrenstorfer’s full range of cannabis reference materials, click here. Or get in touch today to find out how we can assist you, whatever your laboratory’s needs.

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