Almost 90 per cent of US dollar bills have traces of cocaine

In what researchers describe as the largest, most comprehensive analysis to date of cocaine contamination in banknotes, lab tests reveal that cocaine is present in up to 90 per cent of paper money in the US.

In large cities such as Baltimore, Boston, and Detroit, scientists found traces of cocaine in 95 per cent of the banknotes analysed from Washington, DC, alone.

Presenting the findings at the 238th National Meeting of the American Chemical Society, the new study suggests that cocaine abuse is still widespread and may be on the rise in some areas. It could help raise public awareness about cocaine use and lead to greater emphasis on curbing its abuse, researchers say.

Researchers  tested banknotes from more than 30 cities in five countries, including the US, Canada, Brazil, China, and Japan, and found ''alarming'' evidence of cocaine use in many areas.

The US and Canada had the highest levels, with an average contamination rate of between 85 and 90 per cent, while China and Japan had the lowest, between 12 and 20 per cent contamination.

''To my surprise, we're finding more and more cocaine in banknotes,'' said study leader Yuegang Zuo, Ph.D., of the University of Massachusetts in Dartmouth.