Glastonbury Music Festival has been linked to “dangerous” levels of MDMA and cocaine in the adjacent Whitelake River, and scientists believe they’ve found the, uh, number one problem. As BBC reports, public urination by festival goers is dumping toxic levels of drugs into the waterways around Somerset, UK.

The 2020 and 2021 editions of the fest were cancelled due to COVID-19, and the new study looked at Glastonbury 2019. Researchers measured drug levels upstream and downstream of the site before, during, and after the festival. A week later, MDMA concentrations had quadrupled downstream.

It’s unclear if the levels are high enough to effect humans, and this certainly isn’t an argument to open your mouth near people pissing. Part of the problem is that we’re not sure how damaging this waste could be. “We need to raise awareness around drug and pharmaceutical waste,” Dr Christian Dunn of Bangor University said. “It is a hidden, worryingly-understudied yet potentially devastating pollutant.”

And it’s primed to wreak havoc on the surrounding ecosystem, disrupting fish and harming conservation efforts around the rare European eel. “Our main concern is the environmental impact,” Dr. Dunn explained. “This study identifies that drugs are being released at levels high enough to disrupt the lifecycle of the European eel.”

Dan Aberg, a Masters student at Bangor University’s School of Natural Sciences, said, “Illicit drug contamination from public urination happens at every music festival. Unfortunately, Glastonbury Festival’s close proximity to a river results in any drugs released by festival attendees having little time to degrade in the soil before entering the fragile freshwater ecosystem.”

A spokesman for Glastonbury Festival said he was not aware of this specific problem, but said, “Protecting our local streams and wildlife is of paramount importance to us at Glastonbury Festival and we have a thorough and successful waterways sampling regime in place during each festival, as agreed with the Environment Agency.”

He added, “We are aware that the biggest threat to our waterways — and the wildlife for which they provide a habitat — comes from festival goers urinating on the land.” So the next time you go to a festival, save a fish and keep your piss in the public toilets where it belongs.

Environmental impact aside, at least Glastonbury’s biggest problem was liquid. Earlier this year, Elements Festival turned into a literal shit show.