Researchers at Columbia University have found that a notable share of marijuana and tobacco users show elevated levels of metals such as cadmium, mercury, and lead in their bodies. The study reporting these findings was published in Environmental Health Perspectives.
Cannabis is one of the most commonly used substances worldwide. The plant tends to accumulate metals from soil, fertilizers, water, and pesticides. As a result, high concentrations of metals can appear in unfiltered cannabis smoke and in vapors from certain devices used for consumption.
The analysis drew on data from the National Health and Nutrition Examination Survey (NHANES) spanning 2005 to 2018. Among 70,190 participants, 10,921 supplied data on metals detected in blood and urine, with 7,254 adults included in the final analysis.
Regular cannabis users exhibited higher levels of cadmium, mercury, and lead in both blood and urine, particularly if the drug was used within seven days of biosample collection.
Cadmium levels were notably higher in tobacco users, a difference that may reflect variations in usage frequency or the metal’s accumulation in tobacco and cannabis plants alike.
Women who used cannabis tended to have higher urinary cadmium than men. Tobacco use alone correlated with increased concentrations of antimony, barium, cadmium, lead, tungsten, and uranium.
Long-term health implications of these metals remain to be clarified through future research. The scientists also called for investigations into other potential cannabis contaminants to better understand their health effects on users.
Earlier analyses have warned about the risks associated with electronic cigarette products and their emissions.