As a kid, I read the Sherlock Holmes stories and the mysteries of Agatha Christie. As an adult, I wrote four mysteries that focused on a Quaker heroine solving crimes she happened across in her religious community — I published them using my grandmother’s name — Irene Allen — as a pseudonym. And, as a geologist, I have read about real-life criminal investigations that involved samples of sand and soil.
But it was not until I talked with Dr. Nathalie Wall of the chemistry department at Washington State University that I got my head around forensic science that relates to radioactive materials.
“The basic definition of forensics is that it gives you information about the past,” Wall said to me. “The best known type of forensics is the criminal kind.”
Nuclear forensics is the study of radioactive materials found on places like a suspect’s hand. The goal is to develop information about such things as the source of the nuclear material. One part of the research Wall does is to help develop techniques that can be used for prosecution of people linked to illegally transporting or trafficking in radioactive substances.
“A fingerprint belongs to just one person, so it has real importance as evidence,” Wall said. “But you can’t arrest someone just for having a trace amount of uranium on their hands. There is uranium in granite, so a person can pick up trace amounts of it just from handling rocks.”
That is part of the reason why it can be much more complicated to make a legal case against a person for dealing in radioactive materials than it can be to prove other kinds of criminal cases.
“The cool thing about nuclear chemistry is that radioactive elements come in sets or suites,” Wall told me. “If you find a specific suite of elements of different proportions, you can potentially tell where the material came from and what it’s been used for. So this is the ‘fingerprint’ we look for.”
Wall’s work is in the chemistry of various radioactive elements. She collaborates with people who make sophisticated devices for testing trace samples of materials.
“Just as the TSA may swipe your hand to see if you’ve touched conventional explosives, our goal is to develop tests for trace amounts of radioactive isotopes,” Wall said. “Part of the challenge is to make the tests both accurate and fast.”
Wall got a start in the research world working on nuclear repositories and contaminated sites. Nuclear forensics has been a recent addition to her work.
“From a chemist’s point of view, it’s all the same story,” Wall said.
Wall’s work is part of a broader who-done-it effort that’s important to all of us. I am glad she and others like her are at work on real-life investigatory techniques that can stop terrorists.