Dr Richard Bade from UQ's Queensland Alliance for Environmental Health Sciences spoke with 4ZZZ about his study which found more than a dozen new psychoactive substances through an international wastewater surveillance program.
Dr Bade said new psychoactive substances is a definition for compounds that are in theory not controlled under international legislation.
"They are sort of in the grey area of legal and illegal drugs," Dr Bade said.
"It's best to say that they are compounds that mimic conventional recreational drugs such as ecstasy, MDMA, methamphetamine, cannabis etc."