Experts, Studies Warn of Contaminants Found in Legal Marijuana

Some experts are sounding the alarm about chemicals and other contaminants being found in marijuana, including some sold in legalized states, according to a report in The Wall Street Journal.

An alarming number of cannabis users have tested positive for high levels of metals, such as lead and cadmium, in their blood and urine. It's raising concern about contaminants in marijuana that aren't being tested for. Just like all crops, marijuana plants are sprayed with pesticides, and studies have found that these pesticides can be transferred into marijuana smoke.

"Analytical methods for pesticide detection on cannabis are being developed with a view to implementing quality control of cannabis before being sold," a 2020 study explained. "However, no standardized protocol exists."

Some studies have also found rare but detrimental health effects related to marijuana use, such as fungal infections, bleeding of the lungs, and risk of heart attack or failure, particularly amongst those with compromised immune systems.

“Cannabis belongs to a class of plants known as hyperaccumulators, because their tissues can accumulate metals from soil, water, fertilizers, and other sources at levels hundreds or thousands of times greater than is normal for most plants,” a study published last September explained.

The problem isn’t limited to black market cannabis, making it particularly tricky to determine which batches are affected. WSJ reported that one Arizona dispensary recalled the Grim Reefer strain because it may have been tainted by a potentially lethal fungus called Aspergillus. The very same bacteria also forced a recall of the Gelato Orange strain being sold in some California dispensaries.

“It’s a horror story in some ways,” Virginia Commonwealth University professor and forensic toxicologist Michelle Peace told WSJ. “The general belief is that if it’s on the store shelf it must be safe, but it’s hard for the consumer to know.”

Individual states are left to determine their own standards for contaminants in marijuana, with some enforcing strict testing requirements and others taking a more hands-off approach. A former White House Office of National Drug Control Policy adviser told the outlet that cannabis users should maintain a “buyer beware” attitude.

Growers of the crop are split regarding whether or not stricter testing for contaminants would be a good thing or not. Some stand by their product and don’t see how more guidelines would hurt, while some fear it would drive up retail prices and send buyers running back to the black market.

According to a Gallup poll, 17 percent of Americans use marijuana. Cannabis is legal in 38 U.S. states for medical use and in 24 states for recreational use.