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Green screen: University of New Haven professor examines marijuana for contaminants

A professor at the University of New Haven is testing marijuana leaves to study whether they contain hazardous spores and contamination.

While studying marijuana on a federal grant from the Office of National Drug Control Policy, Heather Miller Coyle, an associate professor at the University of New Haven and forensic biologist, began to notice a surprising amount of fungus growth on the leaves her research group was categorizing. She became concerned that the plants, which were being marketed as medical marijuana, might be contaminated and resolved to investigate.

“If this is being distributed as healthy or medicinal, there should be certain levels of certification and quality control,” she said. “We’re looking at not just the chemical composition of the plant, but the bacterial and biological contaminants that are on the surface.”

Coyle began developing a test to identify hazardous substances, such as E. coli or salmonella, which can grow on marijuana. In addition to testing the amount of bacteria, Coyle is also researching varying levels of contamination between synthetic and organic and how bacteria is transmitted when the patient uses different delivery systems.

The tests are intended to prevent medical marijuana users from purchasing products that will cause an allergic reaction or infection from inhaled fungi spores or volatilized pesticides, she said. Without more testing, it is uncertain how users will react to these materials, said Jeffrey Raber, president of The Werc Shop, an independent cannabis lab in California.



“It’s a great unknown really. But there are cases in which, if it is contaminated, exposure to that can create greater health risks,” he said. “To those who are sick or undergoing chemotherapy treatments, I don’t think it’s good to be exposing them to anything else of that fashion.”

In Connecticut, pharmaceutical-grade cannabis is subjected to one of the most stringent medical programs in the United States today, Raber said. Independent testing for mycotoxins and other colony-growing contaminants is required. But because certification of quality is not required and “only as good as the people behind it,” the system can be abused, he said.

Unlike Canada and the Netherlands, where marijuana standards are monitored, the United States federally opposes marijuana use, leaving quality control up to the states, he said. Because each state’s stance on the drug is different, it’s difficult for a universally accepted standard to be established, Raber said.

“My stance is this: They should have a certification program in place where they know what varieties are grown, they can certify the safety and quality,” Coyle said. “I don’t really think there’s so much of an issue for the general public on safety.”

Morgan Fox, communications manager for the Marijuana Policy Project, said the growing number of marijuana quality tests shows an increase in acceptance of its use. Marijuana is, in this usage, an agricultural commodity for consumption and should be treated as such, he said.

“In the illicit market, there’s absolutely no quality control and no regulatory incentives for growers and producers who make sure that their product is untainted by adulterants, molds or pesticides,” he said.

Although Coyle’s tests cannot eliminate the contaminants they find, Raber said, tests finding impurities in medical marijuana will lead to regulation of the substance and greater support to legalize elsewhere.

“I think they’re taking the right approach to ensure that the purity of the compounds are high, and that’s what medicine demands,” he said.

Coyle’s first goal in these tests is to ensure that clean and healthy cannabis can be provided to users in need.

Said Coyle: “From there, and pretty quickly, you’re going to see changes in the way that it’s grown, where it’s grown, and how it’s grown.”





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