Cannabis may contain heavy metals and affect consumer health, study finds

UNIVERSITY PARK, Pa. — Cannabis plants — which are used to produce industrial hemp, medical marijuana and cannabidiol (CBD) oil, among other products — 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 meta-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.

“Heavy metals, such as lead, mercury, cadmium and chromium, are known to be carcinogenic,” said Louis Bengyella, assistant research professor of plant science, Penn State. “The heavy-metal content of cannabis is not regulated; therefore, consumers could unknowingly be exposed to these toxic metals. This is bad news for anyone who uses cannabis but is particularly problematic for cancer patients who use medical marijuana to treat the nausea and pain associated with their treatments.”