The illicit cannabis market could be creating a public health risk after a new study has revealed street weed in Spain to be contaminated with feces.

A team of scientists from the Madrid-based Universidad Complutense conducted the cannabis study, which is yet to be published this May in the journal Forensic Science International.

Pharmacologist José Manuel Moreno Pérez participated in the study alongside the scientists. Based on a report by the BBC, Pérez gathered 90 cannabis samples from black market dealers who sell weed on the streets. His motive for doing so was to determine if the drugs were safe to use. For people living in areas that have not yet legalized cannabis, there is no other choice but to buy from the black market, demonstrating the importance of this study.

Traces of E. coli and Aspergillus fungus found in street cannabis samples

In addition to this, the researchers and Pérez also found traces of fecal matter in the cannabis. Shockingly, 88.3 percent of the samples tested in the study were deemed to be unsafe for consumption.

According to the study, the street cannabis obtained by Pérez was concealed in two types of containers: “ingots” and “acorns.” The researchers stated that “acorns” are commonly smuggled by drug mules into Spain.

As much as 93 percent of the “acorn” samples were contaminated with high levels of E. Coli bacteria. E.coli contamination was also discovered in 29.4 percent of the “ingot” samples. What’s more, 10 percent of all the samples were contaminated with the Aspergillus fungus. 

Researchers determined that the “acorn” samples were more contaminated than the “ingot” samples. Instead of smelling like a potent strain of pot should smell, the “acorn” samples of street weed smelled like fecal matter.

Why? Pérez says that the high levels of contamination and unpleasant odor explains how the drug was smuggled into Spain. He claims that drug dealers in Morocco swallow the plastic “acorns” and wait for them to pass in their stools.

“When they get to Spain, they take a laxative and expel the bellotas,” he explained. “And then they’re put on sale.”

Since they discovered such extortionate levels of contaminants, Pérez, along with the study’s co-authors, claim that their results indicate a “public health issue” in relation to the cannabis being sold on the black market.

“There are no filters on joints,” Pérez told El País. “You are not just breathing in smoke, but also particles.”