If a meeting of the American Chemical Society wouldn't typically catch your attention, this week's Denver gathering may prove an exception. That's after Andy LaFrate presented his pot-themed paper, which had three standout (but not particularly worrisome) findings: retail pot is way more potent, potentially less medically beneficial, and a little dirty. LaFrate runs Charas Scientific; it's one of eight labs certified to test recreational pot in the state, and what it found after examining 600 strains of marijuana from legally certified growers and sellers is that THC—the compound behind pot's "high"—is present in levels as high as 30%, though NBC News reports the average is 18.7%. In the '80s, it was usually below 10%. As Smithsonian explains, that isn't an accidental occurrence: Growers have been crossbreeding strains in a bid to up the potency.
LaFrate tells HealthDay it's not really a big deal, at least in terms of smoking, as smokers can just smoke less. But in that cross-breeding, cannabidiol—that's CBD, a compound that may benefit those suffering from everything from depression to Alzheimer's—has nearly been bred-out. "A lot of the time it's below the detection level of our equipment," says LaFrate. The director of a nonprofit that tracks state marijuana laws isn't wowed by the finding, saying he expects retail pot would be heavy on the THC and light on the CBD. But LaFrate noted that his lab has seen "very little difference between recreational and medical in terms of the THC-to-CBD ratio, at least at the aggregate level." As for it being "really dirty," his lab found fungus (up to 1 million spores, in some cases) on buds, and butane in some pot concentrates. "There's going to be microbial growth on it no matter what you do," he notes. But "what's a safe threshold?" (Would you ever put your pet on pot?)