Scientists Find Dangerous Levels of Fecal Matter in Street Cannabis

A farmer displays a piece of cannabis resin (hashish) near the town of Ketama in Morocco's northern Rif region on Sept. 13, 2017. Fadel Senna/AFP

Scientists have issued a health warning over the high levels of fecal matter found in street cannabis.

Nearly 75 percent of the cannabis bought on the streets of Madrid in Spain was found to be “unsuitable for consumption” due to contamination with E. coli, in a study published in the journal Forensic Science International.

And one in 10 samples had dangerous levels of the fungus Aspergillus.

The dangerous levels of contamination are far worse in cannabis carried inside drug mules who swallow them in plastic pellets.

A pharmacist at a Madrid university spent a year scouring different areas of the city for drug dealers, buying cannabis for testing.

A marijuana plant in Vancouver, Canada, on Oct. 17, 2018. Don Mackinnon/AFP/Getty Images

Manuel Pérez-Moreno, who said he has never smoked cannabis, collected a total of 90 samples, which he tested for various kinds of contamination.

Forty percent of the samples were found to have the aroma of feces.

“The majority of the hash sold in the Madrid region is not apt for human consumption, mainly due to microbiological criteria, and it represents a danger for health,” concludes the study.

The high levels of contamination is partly due to the local modus operandi of the smugglers. The highest levels of E. coli were found in cannabis “acorns”—the term for small plastic pellets swallowed by drug mules who bring it in from Morocco.

A masked farmer walks in a cannabis field near the town of Ketama in Morocco's northern Rif region on Sept. 13, 2017. Fadel Senna/AFP

When the mules arrive in Spain, they take a laxative and expel the acorns, which are passed on to dealers—who may not place hygiene high on their list of priorities.

Researchers found that 93 percent of the acorn samples contained dangerous levels of E. coli bacteria, as did 29 percent of other ingot samples.

Ten percent of the samples were also contaminated with Aspergillus, a dangerous fungus that can cause serious health problems.

Eighty-eight percent were deemed as “not suitable for consumption.”

“This is clearly a public-health problem,” biologist Inmaculada Santos-Álvarez, the co-author of the study told El Pais. “The quantities of bacteria that we found are appalling. The problem is not just inhalation. Hashish is constantly manipulated [by users] with their hands.”

A technician weighs cannabis in a greenhouse near the northern Israeli city of Safed, on Nov. 1, 2012. Menahem Kahana/AFP/Getty Images

Pérez-Moreno warned that burning the cannabis won’t protect people from infection in the way that they might assume. “There are no filters on joints,” he said. “You are not just breathing in smoke, but also particles.”

“It’s a really interesting study,” said psychologist Claudio Vidal from Energy Control, a project that seeks to reduce the risks of drug consumption. But he is cautious, telling El Pais, “It’s a low number of samples, and we don’t know how many batches of hashish were circulating at that time. We can’t know if the results are representative of the hashish that is sold in the Madrid region or in Spain.”

It is illegal to buy, sell, or import cannabis in Spain, or to use it in public. It is technically legal to grow it for personal use and to consume it in private.

The study authors warn that those who use cannabis for medicinal purposes, or to alleviate the side-effects of chemotherapy could be most at risk, reported the BBC.

“These patients have a weakened immune system, meaning that an infection caused by the consumption of contaminated or adulterated hashish could be fatal,” it adds.