As much as 65 percent of $1 bills in the Birmingham area could be contaminated with trace amounts of cocaine, according to a set of experiments conducted by forensic science students at the University of Alabama at Birmingham.

The students tested different methods of measuring the amount of cocaine on money. They looked at 40 $1 bills - half collected from a Regions Bank and half from a Wachovia branch - and found that the more effective testing method revealed 65 percent had cocaine on them. Professor Elizabeth Gardner, who oversaw the research, said the figure matches tests other students conducted in her class with individual $1 bills collected from stores and restaurants around the Birmingham area.

More comprehensive data collected in other cities usually finds between 80 and 90 percent contamination, she said, although those studies usually use higher-denomination bills.

"I have talked to people who say that basically 100 percent of currency is contaminated and if you get any negatives, it's in dollar bills," Gardner said.

As far as she knows, she said, this is the first time the tests have been done on money in Birmingham. However, she cautioned that the research, which was printed in UAB's undergraduate journal Inquiro, was done on a small scale and isn't as complete as previously published studies elsewhere.

The paper was written by student Jeremy Felix for an internship in chemistry with a forensic science track and as an independent honors project by student Rena Hammer. Felix plans to present the results at a meeting of the American Academy of Forensic Sciences.

Gardner also has students in her Justice Science 250 class, titled "Criminalistics: An Overview," conduct similar experiments to trace the amount of cocaine on bills with gas chromatography-mass spectroscopy, a technique commonly used in forensics.

"I think this is something I'm going to have my students do every year," she said. "It is great fun and I think the students really enjoy it, and it is good science."

It's one of several "CSI"-style projects she assigns the class. Others include an analysis of rope and a study of how dog hairs could be transferred from a person petting a dog to a crime scene.

Gardner said she came up with the idea for the cocaine test before coming to UAB last year. She never conducted it at her previous school, but did check with authorities there to make sure it wouldn't get anyone in trouble.

Tiny amount:

She emphasized that the amount of cocaine in question is so tiny that it couldn't possibly affect people who handle the money. Researchers suspect most of the cocaine comes from counting machines at banks, which have been shown to have cocaine dust in them. In addition, Gardner said, the paper U.S. currency is made of seems to attract and trap cocaine residue and other contaminants.

"Money is really dirty," she said.

The first way Gardner had the students test the money - by soaking it in a methanol solution to extract all the contaminants - created a brown liquid too filthy to run through the lab's sensitive machines.

So the students tested three other methods - one in which they used chloroform and water to extract the residues, one in which they used chloroform alone, and one in which they used chloroform and an acid/base wash. They found the latter method produced the cleanest sample, but multiple steps meant a loss of some measurable cocaine. Those samples tested 35 percent positive for cocaine.

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