Public Health and Safety

Heavy Metals: Levels of Lead & Cadmium Pose Health Risks in Cannabis Smokers

When compared to non-smokers, those who smoke exclusively cannabis, daily or near daily, had elevated levels of Lead and Cadmium in their systems. Lead and Cadmium are classified as “Heavy Metals“ that can be harmful to the human body. “Significant exposure to cadmium can cause lung cancer, birth defects and other reproductive harm, while significant exposure to lead can slow children’s growth and development and damage the brain and nervous system”. (Stolbach, A., John Hopkins Toxicologist, NPR, December 17, 2022.)

Researchers McGraw, K. ( are suggesting that marijuana is a source of cadmium and lead exposures in the August edition of Environmental Health Perspectives. They noted that the cannabis plant is a “hyperaccumulator” for metals naturally found in soil, water, chemicals, and pesticides. This study involved over 7,000 participants between 2005 until 2018. 

The authors also noted that smoking both cannabis and tobacco is associated with elevated levels of both cadmium and of lead when compared to non-users of either product. Daily or near daily use increases this exposure risk to the individual.   

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