An academic study carried out at Dublin City University found that every banknote tested was contaminated by traces of cocaine.
Forty-five banknotes were analysed using a chromatography/mass spectrometry process which can detect traces of cocaine up to one part in a trillion. The researchers found that one in 20 notes showed such high levels of contamination that they must have been used directly to snort cocaine, while nearly two-thirds had been in contact with other notes that had been handled by a cocaine dealer or user.
The research was carried out at DCU's national centre for sensor research and funded by the Irish Research Council for Science, Engineering and Technology. It has been published in the Royal Society of Chemistry's journal, the Analyst.
Similar studies worldwide have found very high levels of contamination in banknotes, but this is believed to be the first study to record such a high saturation level. "We were surprised, but not that surprised," said Prof Brett Paull of DCU. "I didn't expect it to be 100 per cent. I expected it to be something like 65 or 70 per cent, in line with other international studies."
He added: "It shows the ubiquity of cocaine in society."
Only notes with a serial number beginning with "T", which indicates they were issued in Ireland, were used. They were tested against notes which had not been in circulation.
PhD student Jonathan Bones said the higher the denomination of the notes, the higher the contamination levels - in keeping with the perception of cocaine as the drug of choice among wealthier members of society. "It's a snapshot of the use of cocaine," he said. "The €20 and €50 notes were much more likely to contain traces of cocaine."
A recent study by the National Advisory Committee on Drugs indicated that an average 25,000 people in Ireland use cocaine every month.
A study published four years ago showed that cocaine use in Ireland had more than tripled among women and doubled among men. A similar study, to be published next month, is expected to confirm that the upward trend has continued.
