The Belgian city of Antwerp is Europe's biggest user of cocaine, leaving behind London and Amsterdam, the newspaper Gazet van Antwerpen reported on Sunday, referring to a new research report. The research studied the waste water of 21 European cities for the traces of cocaine, amphetamines, ecstasy, heroin and methadone to find that Antwerp's sewage water contained the highest cocaine level, the paper said. Antwerp residents also showed a high level of amphetamine and ecstasy use, the report said.