Cerling and Ehleringer over at the University of Utah just published a paper in the online journal "Proceedings of the National Academy of Sciences" describing their new forensic technique, which uses Hydrogen and Oxygen isotope concentrations from local water tables in your hair to determine where you have spend your time.
The two maps here show predicted average hydrogen (top) and oxygen (bottom) isotope levels in human hair across the continental United States -- isotopes that vary with geography because of different isotope levels in local drinking water. The ratios of heavy, rare hydrogen-2 to lighter, common hydrogen -1 are highest in red and orange areas in the top map, and lowest in the blue and darker green areas. The ratios of heavy, rare oxygen-18 to lighter, common oxygen-16 are highest in red and orange areas of the bottom map, and lowest in the blue and darker green areas. Credit: University of Utah
“You can tell the difference between Utah and Texas,” Ehleringer says. But, Cerling adds, “You may not be able to distinguish between Chicago and Kansas City.”
So in case you're considering a life of crime, you might want to
- Consider a new bald or buzz-cut look so the encoded travel history you carry along with you is limited.
- Drink only bottled water
- Shelve any green tendencies and eat at only imported meat and produce.