American researchers have revealed that cannabis could be a source of lead and cadmium contamination.
- Cannabis users have high levels of cadmium in their blood and urine.
- Elevated lead levels have also been found in cannabis smokers.
- Cadmium and lead are heavy metals: the first is carcinogenic, the second has neurological and behavioral effects.
“As the cannabis plant is a known metal sensor, we hypothesized that people who consume it will have higher levels of metal biomarkers than those who do not smoke,” indicated researchers from Columbia University (United States). To test this theory, the team conducted a study in which they used data from the National Health and Nutrition Examination Survey (NHANES) for the years 2005-2018. Then, the scientists classified the 7,254 adults who participated in the survey according to their consumption: no cannabis and tobacco, exclusively cannabis, only tobacco, and dual consumption of cannabis and tobacco. “Five metals were measured in blood and 16 in urine,” they clarified.
High levels of cadmium in the blood and urine of cannabis smokers
According to the results, published in the journal Environmental Health Perspectives, people who reported consuming cannabis exclusively had high levels of cadmium in their blood and urine. As a reminder, cadmium is a bluish-white metal used in several industrial processes, such as the manufacture of electric batteries, the production of pigments, television screens, photography or the metallization of surfaces. “Cadmium is considered a definite carcinogen for humans by the International Agency for Research on Cancer (IARC). Associated cancers are those of the respiratory tract, particularly the lung. Cadmium is, however, suspected of being carcinogenic for cancer prostate and kidney cancer”, signals the Léon Bérard Cancer Center.
Cannabis: “there is no threshold below which exposure to lead would not have harmful effects”
Another observation: high levels of lead have also been discovered in the blood and urine of cannabis smokers. The World Health Organization (WHO) recalls that this toxic substance accumulates in the body and has an impact on multiple organ systems. “There is no threshold below which exposure to lead would not have harmful effects.” At high levels, lead attacks the brain and central nervous system, causing coma, seizures and even death. Low exposure to this substance affects brain development and causes behavioral changes in children. It also causes anemia, hypertension and kidney failure and has toxic effects on the immune system and the reproductive system.
“In the future, research into cannabis use and its contaminants, particularly metals, should be conducted to address public health concerns related to the increasing number of cannabis smokers,” concluded Tiffany R. Sanchez, author of the work, in a statement.
