Cannabis plants may absorb carcinogenic heavy metals such as lead, mercury and cadmium from soils, experts have warned.
Researchers in Pennsylvania have conducted a ‘meta-analysis’ of previous studies to examine the ability of cannabis plants to absorb heavy metals.
They report that some cannabis strains have been bred specifically for ‘phytoremediation’ – growing plants to remove pollutants from soils.
But this risks heavy metals seeping into cannabis crops that are later harvested and smoked by humans, potentially causing cancer and neurological issues.
Heavy metal contaminants could be dangerous for people who ingest them, the researchers say, including cancer patients who use medical marijuana.
The researchers, Penn State University, have therefore proposed strategies for cannabis growers to ensure they avoid heavy metals contaminating their cannabis crops.
‘Heavy metals, such as lead, mercury, cadmium and chromium, are known to be carcinogenic,’ said Louis Bengyella, assistant research professor of plant science at Penn State University.