For two years in a row, scientists have conducted tests before, during, and after the festival in Uppsala north of Stockholm at various locations on the Fyris River, The Local reported Thursday.
"During upcoming festivals the organizers must ensure that there are enough portable toilets in the area and urge the festival-goers not to urinate outdoors, as this is what leads to medical products leaking into the river water," Atlasi Daneshvar in the Department of Aquatic Sciences and Assessment at Uppsala University said.
The most common drug found in the water was ibuprofen, a substance used in many popular painkillers, researchers reported.
More worryingly, they said, remnants of drugs such as epilepsy medicine were measured at levels that could be a direct danger to the environment.
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