Cannabis products are tested for heavy metals, which are generally considered toxic and carcinogenic. Cannabis and hemp plants draw up heavy metals from the soil with an exceptional ability to grow quickly and require few nutrients, allowing them to absorb high volumes of heavy metals such as cadmium, chromium, and lead. In fact, cannabis plants are such a powerful bioaccumulator, they are often used in environmental cleanup efforts and have been used for years to decontaminate soil in contaminated places like the Chernobyl nuclear plant.

Cannabis plants absorb and transport heavy metals into the leaves and flowers, concentrating specifically in the trichomes on the buds, the same place the majority of terpenes and cannabinoids are stored. While trace amounts of some heavy metals are needed for healthy body functioning, like selenium, zinc, and copper, high amounts of these heavy metals cause poisoning. Heavy metal toxicity is considered a public health hazard and has been linked to organ damage and a number of health problems.

Regulations for the cultivation of cannabis vary from state to state, although most states do have protocols for testing plant contamination. The majority of states require testing only for arsenic, lead, cadmium, and Mercury, although each state is different, and some states require testing for additional heavy metals. Problems with heavy metals in cannabis can be solved by instituting regulations that control cultivation. Problems with heavy metals in cannabis affect the consumer, although the solution lies at the agricultural level.