This story originally appeared on Benzinga
Cannabis plants have an inherent ability to absorb heavy metals from the soil, making them useful for remediating contaminated sites. But this ability to soak up toxic metals may also make cannabis dangerous for consumers who ingest it.
A new analysis, led by researchers at Penn State, examines the ability of cannabis plants to absorb heavy metals and discusses the resulting health impacts on consumers. The team proposes a blueprint of strategies for growers to alleviate heavy-metal uptake by their crops, reported medicalxpress.com
“Heavy metals, such as lead, are known to be carcinogenic,” said Louis Bengyella, assistant research professor of plant science at Penn State, who noted that “Consumers could unknowingly be exposed to these toxic metals,” which he called “particularly problematic for cancer patients who use medical marijuana to treat nausea and pain associated with their treatments.”
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Heavy metals can cause cancer and neurological issues
“The problem is if we use these strains that were developed for phytoremediation (to remove pollutants from soil, water, or air), we may unknowingly expose consumers to heavy metals,” Bengyella said.
The team found that that heavy metal contamination in cannabis can cause various health problems due to the fact that the heavy metals accumulate in specific areas of the human body, and cause cancer and neurological issues.
They also noted that heavy metals such as lead, cadmium and chromium, are capable of being transported and distributed up through the stalk and into the leaves and flowers of the plant. These heavy metals then exit the plant through trichomes, which are hairlike structures located on the flowers. Their results were published in a recent issue of Toxin Reviews.
“Trichomes are important because they store the CBD oil and the tetrahydrocannabinol (THC) that are desired by consumers. This led us to question if these heavy metals are there at the level of the trichome, what can they do to people?” said Bengyella who added that “cannabis consumed in combustive form represents the greatest danger to human health, as analysis of heavy metals in the smoke of cannabis revealed the presence of heavy metals such as selenium, mercury, cadmium, lead, chromium, nickel, and arsenic.”
The report’s authors argue that the application of agricultural best practices, such as avoiding abandoned industrial sites and conducting a soil pH test, can mitigate heavy metal contamination because pH can impact the quantity of heavy metals a plant absorbs.