Some marijuana users may have elevated levels of lead and cadmium — two heavy metals linked to long-term health issues — in their blood and urine, a new study shows.

Among a group of more than 7,200 adults, the 358 who reported using marijuana within the past 30 days were found to have 27% higher blood lead levels than those who said they didn’t use either marijuana or tobacco.

The marijuana users also had 22% higher levels of cadmium in their blood, according to the research, which was published Wednesday in the journal Environmental Health Perspectives. Urine samples showed similar results.

The researchers, a team at Columbia University, knew going in that cannabis plants can absorb heavy metals from soil and, in fact, are particularly good at doing so. The contaminants travel through the stalk of the plant into the leaves and flowers.

But the new findings demonstrate that heavy metals in cannabis plants can also wind up in the human body.