Paper Money Tainted with Cocaine

This is Scientific American 60-Second Science. I'm Cynthia Graber. This'll just take a minute.
You're not under arrest, despite the fact that you probably have some drugs in your pocket.
Because there's a good chance your paper money contains trace amounts of cocaine.
According to a study presented August 16th at the American Chemical Society's national meeting, up to 90 percent of American paper bills are contaminated with cocaine.
In Washington, D.C., it's as high as 95 percent.
Some bills had as much as 1,200 micrograms of coke, about equal in size to 50 grains of sand.
But most money had much less.
The finding doesn't mean that all money has directly touched cocaine, although some bills were doubtless used to snort the drug.
Other bills may have picked up coke during drug sales, while most probably just got traces transferred from other bills in banks.
A similar study was conducted two years ago, and at that time about two thirds of American paper money had traces of cocaine.
Researchers aren't sure why there's been a jump, but the new data indicate that cocaine is still a problem.
And the paper clues may reveal which cities have the most users.
Because as any good investigative reporter can tell you, always follow the money.
Thanks for the minute, for Scientific American 60-Second Science. I'm Cynthia Graber.