Experts are raising concerns about the discovery of chemicals and contaminants in marijuana, including some sold in states where it’s legalized.
A concerning number of cannabis users are testing positive for elevated levels of metals like lead and cadmium in their blood and urine, highlighting worries about untested contaminants in marijuana.
According to reports, the use of pesticides on marijuana plants, a common practice, has been found to transfer into the smoke, similar to other crops.
“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.”
Marijuana use is linked to rare but serious health effects such as fungal infections, lung bleeding, and an increased risk of heart attack or failure.
According to multiple studies, these risks are higher in individuals 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,” said a study published last September.
Both legal and illegal cannabis face contamination concerns, making it difficult to identify affected batches. In Arizona, the Grim Reefer strain was recalled from a dispensary due to potential contamination with a dangerous fungus called Aspergillus. A similar issue forced the recall of the Gelato Orange strain in some California dispensaries.
“It’s a horror story in some ways,” said Virginia Commonwealth University professor and forensic toxicologist Michelle Peace. “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.”
Contaminant standards in marijuana vary by state, with some implementing rigorous testing and others adopting a more lenient approach. A former adviser from the White House Office of National Drug Control Policy suggests that cannabis users should adopt a “buyer beware” mentality.
