Heavy Metals Analysis in Hemp Extract Products
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Following the federal descheduling of hemp under the 2018 Farm Bill, many US state legislatures were quick to develop their own hemp crop programs and legalize the cultivation and sale of hemp within their state. In Florida, a 2019 statute legalized the growth and sale of hemp and gave the Florida Department of Agriculture and Consumer Services (FDACS) regulatory authority over the local hemp industry.
Speaking at Analytical Cannabis’ The Science of Cannabis Extraction 2021 online symposium, Diane Pickett, chief of the laboratory within the FDACS’ Division of Food Safety, and Serena Giovinazzi, PhD, environmental manager of the Bureau of Quality Management at the FDACS Division of Food Safety, detailed new results from their laboratory’s research into heavy metal contamination in hemp extracts.
Hemp and food safety in Florida
As defined by the 2018 Farm Bill, the term hemp refers to any plant from the Cannabis sativa species containing less than 0.3 percent THC by weight. Hemp products are therefore any product or substance that is derived from or contains hemp.
“Because hemp extracts are intended to be ingested, they are regulated as food in Florida,” Pickett explained. “And there are many benefits to this; the food industry has been established for over 100 years, this lets us apply all of the knowledge that we've already gained and the lessons we've learned on contamination, sourcing, and packaging issues.”
“This also helps the hemp industry, which is relatively new to food regulations, to not have to reinvent the wheel.”
Just like any other food product, hemp products in Florida must be tested to ensure that they are safe for ingestion. This involves routine testing to ensure the absence of any harmful residual pesticides or biological pathogens in the edible product, as well as cannabinoid-specific testing.
“We have analytical methods for determining cannabinoid content, which we use to evaluate two different potential issues,” Pickett said. “First, we measure the THC, because to be considered hemp it must have less than 0.3 percent THC. We also measure the amount of other cannabinoids, for example CBD, to determine if the label claims are accurate.”
This sampling by FDACS is done at retailers across Florida, collecting products from store shelves and testing their contents. This is different to the tests that producers may do following manufacture, Pickett emphasizes, and is designed to reflect the state of products as they reach the consumer.
Heavy metals in hemp extract products
Heavy metals are a particularly important aspect of hemp product testing. The cannabis plant is a known bio-accumulator, meaning that it readily absorbs minerals and nutrients from the soil it is planted in and accumulate these nutrients in its leaves. While this property makes hemp a useful crop for soil remediation, as it will suck heavy metals and pesticides out of contaminated soil, it proves a problem when the hemp is intended for human use.
Effective heavy metals testing protocols are crucial to protecting consumers from the harms of accidental contamination. As Dr Giovinazzi explained, heavy metal poisoning can result in severe nerve damage, neurological issues, cardiovascular problems, and greatly increase the incidence of certain cancers.
The FDACS Division of Food Safety uses inductively coupled plasma mass spectrometry (ICP-MS) to inspect the products it collects for heavy metal screening. In a recent examination of 206 hemp extract products, the FDACS Division of Food Safety found 10 products to contain lead above the 0.5 parts per million (ppm) regulatory safety limit; two samples contained high enough levels of lead to violate the Resource Conservation and Recovery Act (RCRA) limits for hazardous waste.
“To be honest with you, we have found a greater number of samples than expected to contain toxic heavy metals, lead in particular,” Giovinazzi said. “So, as you can imagine, we immediately started investigating all the possible sources. Is it the plant? Is it arising from the processing? Or the action of manufacturing? Is it the packaging material or container?”
Heavy metal leaching raises concerns
The FDACS Division of Food Safety carried out an additional investigation into the sources of this contamination using information provided by three manufacturers. Presenting data from this ongoing investigation for the first time at the Analytical Cannabis symposium, Giovinazzi revealed that this preliminary data indicates heavy metals are leaching into hemp extract products over time.
For example, one representative product tested in January 2019 returned a lead content of less than 0.01 ppm. When tested again in April, this level had risen to 0.45 ppm, reaching 0.8 ppm by January the following year.
“This prompted us to look more in depth into this issue,” Giovinazzi said. “Our laboratory’s division for inorganic chemistry investigated the leachability of lead in hemp extract packaging material. The study was designed to test packaging components separately – bottles, caps, and graduated droppers – which were produced from two manufacturers.”
“The leaching [study] was conducted with two commonly used carrier oils, hemp seed oil and MCT oil, and measured lead concentration over time.”
In both carrier oils, samples which had been exposed to the graduated droppers showed elevated levels of lead over time, insinuating that these could be a source for lead leaching in finished hemp extracts. FDACS research into the potential sources and preventative measures for heavy metal leaching in hemp oils is still ongoing.
“We do not have all the answers for all contamination identified so far. We are still working on gathering information on all potential sources, such as plant accumulation or extract processing,” Giovinazzi said.
Working with industry to eradicate heavy metal contamination
All of the products identified by FDACS in its market studies were removed from commerce in Florida; two brands also chose to issue nationwide recalls. Moving forward FDACS are continuing to raise awareness about the potential dangers of heavy metal contamination in hemp extracts and will work closely with the industry to identify possible sources.
“We cannot stress enough how important it is to test your extract and packaging material. And we need to make the consideration that testing [...] the finished product after production may not account for lead leaching,” Giovinazzi said.
“We are always seeking ways to collaborate with industry, and with today's [sic] webinar we raise awareness on this issue. Definitely, we urge you to consider the quality and safety testing of your packaging materials, not only your extracts.”
This article originally appeared in Analytical Cannabis' Cannabis Extraction and Processing eBook in April 2022.