Valencia, Spain - Spanish bank notes contain the highest concentrations of cocaine in Europe, according to a study made public on Thursday.
Randomly selected Spanish euro notes contained traces of cocaine at an average concentration of 155 microgrammes, according to the study by Valencia University made public in the magazine Trends in Analytical Chemistry.
Cocaine was found not only on notes that had been in direct contact with the drug, but on nearly all notes in circulation, said Miguel de la Guardia, co-author of the study.
He attributed the phenomenon to cross-contamination between bank notes, as well as in money-counting machines in banks.