WebMD Health News
March 24, 2015 -- Legal marijuana grown in Colorado is two to three times as potent as what was sold on the black market 30 years ago, according to test results released this week at a scientific meeting in Denver.
But it’s the unexpected contents of Colorado’s recreational marijuana that surprised researchers. Scientists found butane, heavy metals, and fungus in some samples.
“It’s pretty startling just how dirty a lot of this stuff is,” said Andy LaFrate, president and director of research at Charas Scientific, in a news release. “You’ll see a marijuana bud that looks beautiful. And then we run it through a biological assay and we see that it’s covered in fungi.”
LaFrate shared the findings at a meeting of the American Chemical Society.
What's in Colorado's Recreational Pot?
Colorado voters legalized recreational marijuana in 2012, with the first legal sales of cannabis in the U.S. in eight decades beginning in 2014.
Mandatory testing for potency began in May 2014, followed by testing for consistency in July 2014, according to Daria Serna, director of communications for the Colorado Department of Revenue.
Charas Scientific is one of eight labs certified by Colorado to test marijuana samples submitted by retailers.
Tests found that, despite the belief that different strains produce different effects on the user, there was little chemical difference among marijuana samples. Researchers also found the levels of THC, the ingredient in marijuana that gives you a "high," ranged from 20% to 30%, compared to the average of 10% 30 years ago. That’s likely a result of years of breeding for higher THC potency many users prefer.
Another effect of this breeding is that recreational marijuana has little to no CBD. That is an ingredient that has shown promise in treating seizures and other medical conditions.
Researchers did not test marijuana edible products or medical marijuana from Colorado.
The state has not yet begun requiring testing for contaminants, but some companies volunteered their products for such tests. Nothing was found to be a serious health risk. But the findings have raised questions about what should be tolerated in marijuana sold to the public and if such contaminants could be harmful.
source : Metals, Fungus Found in Colorado’s Marijuana