Toxins in a wax concentrate are a big concern. They can even block CBD’s medicinal ability to stop seizure activity.
The wax concentrate, like dabs for example, are quickly overtaking edibles as everyone’s second-favorite cannabis product. But while the rapidly rising popularity of the wax concentrate may sound awesome, we still don’t know what the long-term effects of dabbing are.
Contamination can happen with any processed product and a wax concentrate is no different. Waxes extracted with hydrocarbons (like butane or propane) will contain residues of volatile solvents. Even solventless concentrates, like rosin, will generate toxic compounds when vaporizing or smoking.
And as commercial grow operations increasingly rely on pesticides, herbicides, and other poisons to protect their crops, the risk of those poisons transferring into concentrates is concerning for regulators and consumers. What sorts of contaminants may be present in concentrates, and is there any reason to worry about them?
Wax Concentrate and Silent Killers: Pesticides, Herbicides, and Fungicides
A couple of years ago, the U.S.’s premier chemistry organization, the American Chemical Society, formed its Cannabis Chemistry Subdivision to study our favorite plant. Kyle Boyar is a San Diego neuroscientist and analytical chemist at the ACS. When asked about pesticide contamination in concentrates, he told RxLeaf by phone, “It’s a huge problem here in California.”
Boyar noted that there are several ways to clean up concentrates to remove things like herbicides and pesticides from the final product. Contamination can occur through multiple routes, but one of the most common ways is through contamination of the extraction machines themselves.
“Let’s say you get a contaminated batch of trim – it could be Eagle-20, or it could be a million different pesticides in there – and you run it through your closed loop extraction instrument,” he explained. “What you have just done is contaminate your entire instrument.”
There is hope, however. Boyar added, “There are preventative measures people do take, and there are people, especially in the legal markets, to eliminate those problems downstream.”
One of those measures is processing plant material from trusted sources. Hygienic extraction labs will regularly test batches of plant material and their instruments to ensure pesticide, herbicide, and other nasty residues don’t get stuck to the interiors of columns and tanks.
Fuel Sources: Hydrocarbon Solvents
The extraction process of most cannabis concentrates occurs with hydrocarbons such as butane and propane, organic compounds that are both incredibly volatile and insidiously toxic in high amounts. Legal weed states require processors to purge concentrates with heat and vacuum filtration, but these processes always leave some residual solvent in the oil.
When asked if butane or propane residues should worry cannabis consumers, he replied, “In my personal opinion: No. If you have concerns about it, you probably shouldn’t be consuming it anyway.”
According to Boyar, cannabis smokers inhale more butane from a lighter hitting a glass pipe than they ever would from “the dirtiest concentrate,” AKA shatter. “The tolerance for something like that is very high,” he said. “You’d have to be inhaling tons of it, enough to visibly see it, for it to be a problem.”
Under the Radar: Mycotoxins
Although Boyar believes most cannabis labs properly screen for the obvious contaminants, there is one potential issue that no one’s talking about: mycotoxins
Mycotoxins are toxic metabolites that fungi produce. In 2016, one study found that penicillium was contaminating cannabis samples sold in Amsterdam and Massachusetts. Penicillium, the fungus we get penicillin from, also produces a mycotoxin called paxilline. Paxilline can trigger tremors, and it can block CBD’s ability to stop seizures.
“It has profound implications for people who are epileptic,” Boyar warned, largely because compounds like paxilline is trick to remove from concentrates. “Mycotoxins are incredibly stable. They’re resistant to heat, and you can’t get rid of them with distillation.”
Unfortunately, the prevalence of mycotoxin contamination remains unclear. Boyar said there isn’t enough data right now because most labs don’t test for mycotoxins, and the ones that do only screen for “a handful.”
Double-Edged Sword: Terpene Degradation Products
Another danger from concentrates isn’t exactly contamination. Rather, it’s a consequence of dabbing based on the plant’s natural chemistry. We often talk about terpenes as the next big trend in cannabis, whether medicinal or recreational. Terpenes are aromatic compounds that give cannabis its unique flavor and bouquets, and there’s some evidence that terpenes may determine what kinds of highs we experience, too.
However, some terpenes have some downsides. Pinene, is a terpene that smells like pine needles. It can act as a nervous system stimulant. However, it can irritate tissues in small amounts. Massive doses of pinene can trigger seizures in susceptible individuals. Most concentrates, thankfully, will never deliver the amount of terpenes to make them dangerous. But heating and combustion of terpenes can degrade these tasty molecules into carcinogens and neurotoxins.
Last year, Robert Strongin’s research group at Portland State University in Oregon looked at terpene degradation from dabbing. The study, published in ACS Omega (2017) mimicked conventional dabbing by dropping concentrates onto heated nails, pulling the vapor through a water filter, then chemically analyzing the vapor’s contents at the other end.
One of the major terpene degradation products Strongin’s group detected was methacrolein. Methacrolein, also known as methacrylaldehyde, can irritate the eyes and respiratory system. Its formation during dabbing may explain why dabs cause some people to cough and tear up more than smoking does.
Another terpene degradation product generated by dabbing is benzene, one of the chemicals that makes tobacco smoke highly carcinogenic.
“Terpenes are ubiquitous in our environment,” Strongin said over the phone. “Their degradation pathways are very well known. What we saw was really no surprise.”
Smoking Also a Risk for Terpene Degradation
Strongin noted that terpene degradation products don’t just come from dabbing. Smoking cannabis also generates these nasty little molecules, too.
Strongin stressed that he was not a medical doctor and could not give medical advice. He did, however, suggest cannabis consumers should “dab at lower temperatures with as much control as you can.”
That means don’t hit the rig when the nail is still red hot. If the nail features temperature settings, he said it’s wise to use the lowest setting possible. “Any level of benzene is bad,” Strongin said, “but the lower the temperature, the more likely you are to limit your exposure.”