Study: 90 percent of US currency is drug money — literally

Your money is on drugs.

That’s the conclusion, more or less, of a study that found 90 percent of the paper currency in circulation in the United States carries trace quantities of cocaine.

What’s more, this represents a more than 20 percentage point increase over a similar study carried out two years ago, researchers point out, when 67 percent of US bills were found to have traces of cocaine.

Researchers at the University of Massachusetts studied samples of dollar bills in circulation and found that bills containing cocaine are concentrated “particularly in large cities such as Baltimore, Boston, and Detroit. The scientists found traces of cocaine in 95 percent of the banknotes analyzed from Washington, D.C., alone,” states a press release from the American Chemical Society.

Salt Lake City, meanwhile, was found to have the lowest rate of contamination.

The study also looked at currency in four other countries — Brazil, Canada, China and Japan — and found that the numbers are similar for Canada and Brazil, but much lower for China and Japan. Eighty-five percent of Canadian paper currency was contaminated with cocaine; 80 percent of Brazilian reals were contaminated. By contrast, in China and Japan that number ranged from 12 to 20 percent.

But the discovery of cocaine on 90 percent of bills does not mean that anywhere near 90 percent of the population is using cocaine. As Janet Raloff explains at Science News, trace elements of cocaine get stuck in the folds of the bills and remain there indefinitely, so as bills circulate, they eventually pass through the hands of cocaine users and become permanently contaminated.

“The US Office of National Drug Control Policy reports that more than 2 million Americans used cocaine in 2007,” Scientific American reports. “The United Nations Office on Drugs and Crime, for its part, reported in the same year that 6 million Americans admit using cocaine annually, consuming a total of as much as 457 metric tons in a year.”

Six million Americans is roughly two percent of the population.

RECESSION TO BLAME?

The most perplexing aspect of the study is the 20-percent increase in the frequency of contaminated bills over the past two years.

“I’m not sure why we’ve seen this apparent increase, but it could be related to the economic downturn, with stressed people turning to cocaine,” Yuegang Zuo, the head researcher in the study, said.

It’s worth noting that the sample sizes used for the study were very small — for instance, only 27 Canadian dollar bills were studied, and the total amount of US greenbacks analyzed was fewer than 250.

And for those of you who think you may have found a new use for the dollar bill, note that “for the most part, you can’t get high by sniffing a regular banknote,” according to Zuo. “It also won’t affect your health and is unlikely interfere with blood and urine tests used for drug detection.”